I am 8 months pregnant, and I think we finally settled on a name. [name_f]Holiday[/name_f] 
We have a pretty simple last name, and are looking for a middle name that would sound classy and classic, and offer her an alternative name to go by if she chooses.
Thanks for your help!
[name_f]Holiday[/name_f] is gorgeous. I keep thinking of [name_u]Billie[/name_u] [name_f]Holiday[/name_f] ([name_u]Jazz[/name_u] Singer) or [name_f]Holliday[/name_f] [name_m]Granger[/name_m] (absolute stunning actress).
Some ideas (without knowing your personal tastes)
[name_f]Anne[/name_f]/[name_f]Annabelle[/name_f]
[name_f]Frances[/name_f]
[name_f]Claire[/name_f]/[name_f]Clara[/name_f]
[name_f]Mae[/name_f]/[name_f]Maeve[/name_f]
[name_f]Charlotte[/name_f] (lots of nicknames)
[name_f]Elizabeth[/name_f] (lots of nicknames)
Or perhaps a word-name or virtue-name?
I’ve kept it pretty basic. If you hate them all, here’s some to scrap off your list 
I agree with using a classic middle if you’re using something as quirky as [name_f]Holiday[/name_f] (which is a name I love).
Maybe
[name_f]Holiday[/name_f] [name_f]Elisabeth[/name_f]
[name_f]Holiday[/name_f] [name_f]Catherine[/name_f]
[name_f]Holiday[/name_f] [name_f]Margaret[/name_f]
[name_f]Holiday[/name_f] [name_f]Madeleine[/name_f]
I love [name_f]Holiday[/name_f]! My favourites are in bold…
[name_f]Holiday[/name_f] [name_f]Veda[/name_f]
[name_f]Holiday[/name_f] [name_f]Juno[/name_f]/[name_u]Juniper[/name_u]
[name_f]Holiday[/name_f] [name_f]Olympia[/name_f]
[name_f]Holiday[/name_f] [name_f]Phoebe[/name_f]
[name_f]Holiday[/name_f] [name_f]Emma[/name_f]
[name_f]Holiday[/name_f] [name_f]Constance[/name_f]
[name_f]Holiday[/name_f] [name_f]Verity[/name_f]
[name_f]Holiday[/name_f] [name_f]Annabel[/name_f]
[name_f]Holiday[/name_f] [name_f]Violet[/name_f]
[name_f]Holiday[/name_f] [name_f]Jessamine[/name_f]
[name_f]Holiday[/name_f] [name_f]Olivia[/name_f]
[name_f]Holiday[/name_f] [name_f]Solana[/name_f]
[name_f]Holiday[/name_f] [name_f]Amara[/name_f]
[name_f]Holiday[/name_f] [name_f]Aminta[/name_f]
I personally prefer [name_f]Holliday[/name_f] (like the lovely [name_f]Holliday[/name_f] [name_m]Grainger[/name_m]) because it gives it less of a word-turned-name feel.
I agree that a middle for [name_f]Holiday[/name_f] should be classic to weigh it up a little. I love the suggestion of [name_f]Holiday[/name_f] [name_f]Catherine[/name_f] and [name_f]Holiday[/name_f] [name_f]Elizabeth[/name_f]. A few other suggestions:
[name_f]Holiday[/name_f] [name_f]Beatrice[/name_f]
[name_f]Holiday[/name_f] [name_f]Cordelia[/name_f]
[name_f]Holiday[/name_f] [name_f]Elise[/name_f]
[name_f]Holiday[/name_f] [name_f]Georgiana[/name_f]
[name_f]Holiday[/name_f] [name_f]Patricia[/name_f]
[name_f]Holiday[/name_f] [name_f]Rosamund[/name_f]
Would have suggested [name_f]Holiday[/name_f] [name_f]Juno[/name_f], but that might be a bit too much? I also love [name_f]Holiday[/name_f] [name_u]Hero[/name_u] but that’s probably too much of an alliteration and it gives the combination a rather “saver of the vacation” feel.
Oh my goodness, makes my day to see someone praising [name_f]Holiday[/name_f]! It’s been one of my favorites for quite awhile now. My current combo is [name_f]Holiday[/name_f] [name_f]Anastasia[/name_f] [name_f]Claire[/name_f]. You’ve got loads of great suggestions already, but I’ll give it a shot. Sorry for repeats.
[name_f]Holiday[/name_f] [name_f]Claire[/name_f]
[name_f]Holiday[/name_f] [name_f]Josephine[/name_f]
[name_f]Holiday[/name_f] [name_f]Emmeline[/name_f]
[name_f]Holiday[/name_f] [name_f]Cordelia[/name_f]
[name_f]Holiday[/name_f] [name_f]Isabelle[/name_f]
[name_f]Holiday[/name_f] [name_u]Sage[/name_u]
[name_f]Holiday[/name_f] [name_f]Elle[/name_f]
[name_f]Holiday[/name_f] [name_f]Elizabeth[/name_f]
[name_f]Holiday[/name_f] [name_f]Aurora[/name_f]
[name_f]Holiday[/name_f] [name_f]Seraphine[/name_f]
[name_f]Holiday[/name_f] [name_f]Maya[/name_f]
[name_f]Holiday[/name_f] [name_f]Maeve[/name_f]
[name_f]Holiday[/name_f] [name_f]Eva[/name_f]
[name_f]Holiday[/name_f] [name_f]Eloise[/name_f]
[name_f]Holiday[/name_f] [name_f]Isla[/name_f]
[name_f]Holiday[/name_f] [name_f]Juliet[/name_f]
[name_f]Holiday[/name_f] [name_f]Lucia[/name_f]
[name_f]Holiday[/name_f] [name_f]Lisette[/name_f]
[name_f]Holiday[/name_f] [name_u]Skye[/name_u]
[name_f]Holiday[/name_f] [name_u]Blaire[/name_u]
[name_f]Holiday[/name_f] [name_f]Willow[/name_f]
Best of luck! I would love to hear what you decide on!
[name_f]Holiday[/name_f] is very, very cute. I love it. 
[name_f]Holiday[/name_f] [name_f]Jane[/name_f]
[name_f]Holiday[/name_f] [name_f]Margaret[/name_f]
[name_f]Holiday[/name_f] [name_f]Caroline[/name_f]
[name_f]Holiday[/name_f] [name_f]Catherine[/name_f]
[name_f]Holiday[/name_f] [name_f]Isobel[/name_f]
[name_f]Holiday[/name_f] [name_f]Anneliese[/name_f]
[name_f]Holiday[/name_f] [name_f]Florence[/name_f]
[name_f]Holiday[/name_f] [name_f]Lucia[/name_f]
[name_f]Holiday[/name_f] [name_f]Madeline[/name_f]
[name_f]Holiday[/name_f] [name_f]Magdalene[/name_f]
[name_f]Holiday[/name_f] [name_f]Vivienne[/name_f]
[name_f]Holiday[/name_f] [name_f]Jane[/name_f]! That was my favorite suggestion.