This is such a fun challenge! First some feedback:
[name_m]Olaf[/name_m] / [name_m]Olav[/name_m] - With the wildly popular Frozen character, [name_m]Olaf[/name_m] is now such a household name that I genuinely don’t think you’ll get saddled with the [name_u]Ollie[/name_u] nickname. If you’re concerned about it, I think [name_m]Olaf[/name_m] would be a gorgeous middle name choice.
[name_m]Lars[/name_m] - I used to be rather cold toward this name, but the [name_m]Steven[/name_m] Universe character really brought it to life for me! The character’s arc is amazing - he starts out as one of those people who is trying painfully hard to be one of the cool kids and kind of acts like a jerk to his friends, but over the course of the series, he becomes so selfless and courageous. It’s a beautiful story!
[name_m]Niels[/name_m] - I do like this name for you, but if it doesn’t feel like the one, I understand. I love that it can be a nickname for [name_m]Cornelius[/name_m]!
[name_m]Leif[/name_m] - I love that this is a homophone with the nature name [name_u]Leaf[/name_u], but I think I love the “layf” pronunciation even more.
[name_m]Bjorn[/name_m] - I adore this name for you! So handsome and strong, and the bear connection creates some precious nickname possibilities.
[name_m]Sven[/name_m] - I’m not as keen on [name_m]Sven[/name_m]. I think it’s the stereotypical Scandi name the way [name_m]Ivan[/name_m] is the stereotypical Russian name, if that makes sense. There’s also the reindeer.
[name_m]Soren[/name_m] - This is my favorite name on your list. I love the soaring open vowel of the first syllable with the strength of the -en ending. It sounds grave and starry and powerful. [name_u]Love[/name_u] this for you!
Now on to the suggestions!
[name_m]Alvar[/name_m] - Swedish from Old Norse meaning “elf warrior”
[name_m]Ernst[/name_m] - form of [name_m]Ernest[/name_m]
[name_m]Stellan[/name_m] - beautiful starry name from Old Norse meaning “calm” - love this for you!
Jarl - means “chieftan”
Acke - means “peace of the father”
[name_m]Thor[/name_m] / [name_m]Tor[/name_m] - name of the Norse god of thunder. Other variants include [name_m]Thorvald[/name_m] / [name_m]Torvald[/name_m] ([name_m]Thor[/name_m]'s ruler), Thorbjörn / Torbjörn ([name_m]Thor[/name_m]'s bear), [name_m]Thorsten[/name_m] / [name_m]Torsten[/name_m] ([name_m]Thor[/name_m]'s stone), Torgny ([name_m]Thor[/name_m]'s noise), [name_m]Torkel[/name_m] ([name_m]Thor[/name_m]'s cauldron), Truls / Þórgísl ([name_m]Thor[/name_m]'s staff), and Thore / [name_m]Tore[/name_m] / Ture ([name_m]Thor[/name_m]'s warrior).
[name_m]Henrik[/name_m] - Scandi form of [name_m]Henry[/name_m]
[name_m]Melker[/name_m] - Swedish form of [name_m]Melchior[/name_m]
Sture - three viceroys of [name_u]Sweden[/name_u] bore this funky name that means “to be contrary” in Old Norse
[name_m]Ville[/name_m] - Swedish diminutive of [name_m]William[/name_m]
Ansgar - meaning “spear of God”
[name_m]Loke[/name_m] - modern Scandinavian version of [name_u]Loki[/name_u]
[name_m]Kalle[/name_m] - diminutive of [name_m]Karl[/name_m]
[name_m]Salomon[/name_m] - variant of [name_m]Solomon[/name_m], meaning “peace”
Orvar - means “arrow” in Old Norse
[name_m]Gottfrid[/name_m] - Swedish form of [name_m]Godfrey[/name_m]
[name_m]Carl[/name_m] - Too common? I love the Jung association.
[name_m]Ruben[/name_m] - Scandi form of [name_m]Reuben[/name_m] and name of an Armenian king
[name_m]Tage[/name_m] - from medieval Danish [name_f]Taki[/name_f], meaning “to capture”
[name_m]Mats[/name_m] - means “the gods are present”
[name_m]Sigurd[/name_m] - from Old Norse meaning “guardian, protector.” Other forms include [name_m]Sigge[/name_m], [name_m]Sigfrid[/name_m], [name_m]Sigmund[/name_m], and Sigvald.
[name_m]Rolf[/name_m] - Variant of [name_m]Ralph[/name_m] and [name_m]Rudolph[/name_m] (too similar to your son’s name, maybe)
[name_m]Jens[/name_m] - Danish form of [name_m]John[/name_m], also reminds me of [name_u]Jensen[/name_u]
[name_m]Frans[/name_m] - form of [name_u]Francis[/name_u]
[name_m]Arvid[/name_m] - means “tree of the eagle”
Trygve / Tryggve - from Old Norse tryggr meaning “trustworthy”
Gudmund - means “God is protecting”
[name_m]Erling[/name_m] - “descendant of the jarl”
[name_m]Kennet[/name_m] - Scandinavian form of [name_m]Kenneth[/name_m] - love this for you!
Hemming - means “changing shapes”
[name_m]Viggo[/name_m] - Swedish short form of [name_m]German[/name_m] names meaning “war”
[name_f]Mille[/name_f] - Swedish short form of [name_m]Emil[/name_m]
[name_m]Severin[/name_m] - Scandi form of [name_m]Severus[/name_m], meaning stern; also a secret [name_m]Harry[/name_m] [name_m]Potter[/name_m] reference! - love this for you
Kjell - meaning “kettle, helmet, or cauldron”
[name_m]Lennart[/name_m] - Swedish and Low [name_m]German[/name_m] variant of [name_m]Leonard[/name_m]
[name_m]Rune[/name_m] - Scandi word name meaning “secret lore”
Hasse - means “the gods are merciful”
[name_m]Vidar[/name_m] - a Norse god of the forest who will avenge [name_m]Odin[/name_m]'s death at Ragnarok
[name_m]Greger[/name_m] - Swedish form of [name_m]Gregory[/name_m]
[name_m]Sixten[/name_m] - from Old Norse meaning “stone of victory”
[name_u]Janne[/name_u] - Finnish and Swedish form of [name_m]John[/name_m] / [name_u]Jan[/name_u]
[name_m]Mikkel[/name_m] - means “which man is like God?”
[name_m]Ulf[/name_m] - from Old Norse ulfr meaning “wolf”
[name_m]Osvald[/name_m] - Scandi cognate of [name_m]Oswald[/name_m]
[name_u]Inge[/name_u] - diminutive of [name_m]Ingemar[/name_m], Ingvald
[name_m]Nils[/name_m] - Scandi form of [name_m]Nicholas[/name_m]
[name_m]Magnus[/name_m] - the name of three kings of [name_u]Sweden[/name_u]
[name_m]Harald[/name_m] - Scandi cognate of [name_m]Harold[/name_m], means “powerful man in the army”
[name_m]Roffe[/name_m] - means “legendary wolf”
[name_m]Svante[/name_m] - Swedish short form of a complex Cyrillic name meaning “blessed people” - a great alternative to [name_m]Sven[/name_m]
Varg - means “wolf” in Old Norse
[name_m]Einar[/name_m] - a bit of a melancholy meaning - “one who fights alone”
[name_m]Anders[/name_m] - Scandinavian form of [name_m]Andrew[/name_m]
[name_m]Knut[/name_m] - Danish prince
[name_m]Ulrik[/name_m] - Scandi form of [name_m]Ulrich[/name_m], meaning “prosperity and power”
[name_m]Stefan[/name_m] / [name_m]Staffan[/name_m] - Swedish forms of [name_m]Stephen[/name_m]
Halvar - Swedish variant of Norwegion [name_m]Halvard[/name_m], “rock guardian”
[name_m]Gillis[/name_m] - Swedish form of [name_m]Giles[/name_m]
[name_m]Valentin[/name_m] - Scandinavian form of [name_u]Valentine[/name_u]
[name_m]Folke[/name_m] - “of the people”
[name_m]Casper[/name_m] - Scandi form of [name_m]Jasper[/name_m]
[name_m]Noak[/name_m] - Swedish form of [name_u]Noah[/name_u] - love this for you!
[name_m]Rikard[/name_m] - Scandi form of [name_m]Richard[/name_m], also a GOT name
[name_m]Krister[/name_m] - Swedish variant of [name_m]Christopher[/name_m]
[name_m]Sten[/name_m] - means “stone, small rock”
[name_m]Hjalmar[/name_m] - “helmeted warrior”
Göran / Jörgen / Örjan - Swedish versions of [name_m]George[/name_m]
[name_m]Rasmus[/name_m] - Scandi and Estonian form of [name_m]Erasmus[/name_m], meaning “beloved”
Peer - a variant of [name_m]Peter[/name_m] used by a Norwegian playwright for the main character in Peer Gynt. Other forms of [name_m]Peter[/name_m] include [name_m]Pehr[/name_m], [name_m]Pelle[/name_m], [name_m]Peder[/name_m], [name_m]Per[/name_m], and [name_m]Petter[/name_m]
[name_m]Dag[/name_m] - meaning “day”
[name_m]Oskar[/name_m] - Scandinavian version of [name_m]Oscar[/name_m], meaning “deer friend”
[name_m]Isac[/name_m] / [name_u]Isak[/name_u] - Scandi forms of [name_m]Isaac[/name_m]
[name_m]Valdemar[/name_m] - Scandinavian form of [name_m]Waldemar[/name_m] / [name_m]Vladimir[/name_m] and the name of four kings of Denmark
Ludde - Swedish diminutive of [name_m]Ludvig[/name_m], the Scandi version of [name_m]Ludwig[/name_m]
[name_m]Edvard[/name_m] - form of [name_m]Edward[/name_m]
[name_m]Lasse[/name_m] - Finnish diminutive of [name_u]Laurence[/name_u]
[name_m]Strom[/name_m] - Swedish name meaning “river, current” - love this for you!
[name_m]Hans[/name_m] - Scandi short form of [name_m]Johannes[/name_m]
Klas - Swedish short form of [name_m]Nicholas[/name_m]
[name_m]Axel[/name_m] - Danish form of [name_m]Absalom[/name_m], “my father is peace”
[name_m]Gunnar[/name_m] / Gunne - Swedish name from Old Norse legend
[name_m]Ragnar[/name_m] - Scandinavian cognate of [name_m]Rayner[/name_m], also a famous Viking
[name_m]Fredrik[/name_m] - Swedish king
Olander - means someone from the island Öland or Åland in [name_u]Sweden[/name_u]
[name_m]Lorens[/name_m] - Scandi variant of [name_u]Laurence[/name_u]
[name_m]Njord[/name_m] - Old Norse god of the sea - love this for you!