Thank you all for your feedback. It’s been quite thought provoking. Hopefully we can make a decision soon! I’d sure like to get her some personalized items made-- before she arrives! 
I like [name]Lilian[/name] [name]Isabelle[/name] best from your list, [name]Lily[/name] [name]Belle[/name] is just adorable.
Because your son’s names both end in N, it seems natural to go for [name]Lillian[/name], which is my personal favourite anyway.
[name]Lillian[/name] [name]Rose[/name] also seems to be the best way to honour your dad too. Although I do like [name]Lillian[/name] [name]Isabella[/name] (and [name]Lily[/name] [name]Belle[/name] is sweet!)
I love [name]Lillian[/name] [name]Isabelle[/name]!
[name]Lillian[/name] [name]Isabelle[/name] is perfect. Very lovely.
[name]Lillian[/name] [name]Isabelle[/name] seems like a lot of l’s, and a bit long and sing-song-y (both names are 3 syllables, stress on the first syllable).
I love [name]Lillian[/name], and I don’t find it dated in a bad way at all (in fact, I find it a lot less dated than some of the other favourites on this site - like [name]Penelope[/name]).
I don’t really ‘get’ [name]Hadley[/name]. It sounds boyish, faddish and made-up (not saying that it is), to me.
[name]Lillian[/name] [name]Rose[/name], [name]Lillian[/name] [name]Eve[/name], [name]Lillian[/name] [name]Jane[/name], [name]Lillian[/name] [name]Pearl[/name].
I find [name]Lillian[/name] [name]Rose[/name] so beautiful and feminine! I love all of your names, but [name]Lillian[/name] [name]Rose[/name] is my favorite.
My favorite is [name]Lillian[/name] [name]Isabelle[/name] b/c [name]Lily[/name] [name]Belle[/name] is a beyond adorable nickname :). I also like [name]Lillian[/name] [name]Rose[/name]. I’m not as much a fan of [name]Hadley[/name]; the name is nms.
Very nice comments and advice, everyone. To me, [name]Lillian[/name] [name]Isabelle[/name] is the #1 choice because it’s so much more feminine than [name]Hadley[/name] and because [name]Lillian[/name] [name]Rose[/name] is TWO flower names which always feels a bit odd to me. And as everyone said, [name]Lily[/name] [name]Belle[/name] is adorable!
[name]Lillian[/name] [name]Isabelle[/name] ([name]Lilly[/name] [name]Belle[/name]) by a mile, it is the best one, I do like [name]Hadley[/name] [name]Rose[/name] too, but I love love [name]LOVE[/name] [name]Lilly[/name] [name]Belle[/name]/[name]Lillian[/name] [name]Isabelle[/name].
I think [name]Lillian[/name] [name]Isabelle[/name] is my top choice because [name]Lilly[/name] [name]Belle[/name] is just soooo sweet. [name]Lillian[/name] [name]Rose[/name] is lovely too. [name]Hadley[/name], eh, yuck…where did that come from?