You ask a difficult question [name]Nephele[/name], but I’ll try my best to answer ^^
Through time, Norway has been colonised, by Denmark and [name]Sweden[/name] in many turns… As the Norwegian language developed itself more, and the written word became more and more important, Norway was a part of Denmark, and a Danish “accent” was considered evidence of high class and whatnot… Norway used Danish as the written language at that time, but the need for a true Norwegian written language became apparent as we got our own constitution and such (1814) and through the 1800’s two guys went in different directions trying to make a Norwegian written language…
One guyt ([name]Knud[/name]) used our Danish heritage as inspiration, but making the written word more true to the Norwegian pronunciation, mainly that in the cities and the language of the “educated”.
The other ([name]Ivar[/name]) travelled across Norway and documented the different dialects he found in every remote village and valley and such and compiled a dictionary with grammar and everything based on that, the actual language spoken across Norway, finding similarities and common ground between all the different dialects (and we have MANY, and they are all much more different from one another than a lot of dielects within the English language)…
From what I can tell and remember, [name]Ivar[/name] published his dictionary and grammar between 1848 and 1850. [name]Knud[/name]'s published his first article on the subject in 1845, but no grammar was published until 1907 or thereabouts, after his death… I’m not too sure… this is the part of school most people HATE because it’s so complicated and unnecessary to walk around and remember! ^^
I hope that answers for you, I don’t know anything further back, but both Danish and Norwegian are Germanic languages, and developed from Old Norse (I think) so it’s really the 1800 stuff that matters… 
And about girls’ names ending in A, I love too many of those, I always get in trouble trying to make good combos, because most of the girls’ names end in A, and I don’t like alliteration, be that of the first or last letters of the names…
[name]Edit[/name] for [name]Susan[/name] ^^
I guess [name]Lilja[/name] and Lilje would be pronounced something like [name]LIL[/name]-yah and [name]LIL[/name]-yeh if that’s enough of a difference for you… We have a lot more vowel sounds in Norwegian than you have in English, so it’s kind of hard for me to portray it accurately… For instance, it’s absolutely BEYOND me how anyone can take an I or an O in a name and just change it into a Y or something and expect the pronunciation to be the same! It’s just ridiculous!! In Norway, [name]Lin[/name] and [name]Lyn[/name] mean two completely different things, but the pronunciation is so distinct, no one would mistake one for the other!
And Yes, Finnish culture is very different from the other Scandinavian nations… For starters, I understand both Danish and Swedish without trouble and could probably wrap my head around Icelandic if I wanted to, but Finnish might as well be Mandarin to me because I have no clue as to what they’re talking about! I have no idea why there’s such a difference though… Finland was not our main focus in school one could say ^^; It might be because [name]Sweden[/name], Denmark and Norway have had a very conjoined history, if that makes sense? We’re kind of like siblings who grew up together, Finland being the stepbrother who came in after we were all grown up… Scandinavia for me does not include Finland. Not that I have anything against Finland, quite the opposite, it’s just a feeling of mine ^^ I think Finland being part of Scandinavia is something the rest of the world thinks, but not the Scandinavians themselves… I’m only speculating of course, it’s really hard to say anything… If you ask a [name]Swede[/name], you’ll probably get a completely different view of it all, because [name]Sweden[/name] and Finland have a very close relationship ^^