We would definitely consider using full names. Unfortunately, our little guy’s cousin already has the nickname [name_m]Mac[/name_m], so can’t do that. Thanks for your input!
[name_u]Sullivan[/name_u] [name_u]Francis[/name_u] has better flow, [name_f]IMO[/name_f]. But I like [name_m]Cormac[/name_m] much more than [name_u]Sullivan[/name_u]. [name_u]Francis[/name_u] [name_u]Sullivan[/name_u] nn [name_u]Frankie[/name_u]? 
Nickname [name_u]Sully[/name_u] easily wins over [name_u]Mickey[/name_u] for me, though I do like [name_u]Sullivan[/name_u] and [name_m]Cormac[/name_m]. I also like [name_u]Sullivan[/name_u] [name_f]Frances[/name_f] “[name_m]Becker[/name_m]” best because of the 3-2-2 syllable flow. [name_m]Cormac[/name_m] [name_m]Thomas[/name_m] “[name_m]Becker[/name_m]” is 2-2-2 and that’s not as interesting [name_f]IMO[/name_f].
[name_m]Both[/name_m] are really nice names though, good luck!
[name_u]Sullivan[/name_u] [name_u]Francis[/name_u]! I adore the full name, and [name_u]Sully[/name_u] is just adorable. 
I would love to see [name_u]Sullivan[/name_u] [name_m]Thomas[/name_m], too, but I think I actually like [name_u]Sullivan[/name_u] [name_u]Francis[/name_u] better (which is rather shocking to me; I’m not the hugest fan of [name_m]Frank[/name_m] names in general. :)).
Good luck!
I would wait until you see him to make the final decision. That being said, I personally like [name_u]Sullivan[/name_u] slightly more than [name_m]Cormac[/name_m].
As a combo, [name_u]Sullivan[/name_u] [name_u]Francis[/name_u] sounds exceptional.
Thanks, all, for your input! While the nicknames are just an option (not definite), it’s nice to know what people think. At this point, we may just wait and see what our little guy looks like!
I voted for [name_u]Sullivan[/name_u] [name_u]Francis[/name_u], because I like [name_u]Sullivan[/name_u] better than [name_m]Cormac[/name_m] and I [name_f]LOVE[/name_f] [name_u]Francis[/name_u]! It sounds so classy and soft but strong. Would you consider [name_u]Francis[/name_u] [name_m]Cormac[/name_m]? ([name_u]Francis[/name_u] [name_u]Sullivan[/name_u] doesn’t work [name_f]IMO[/name_f] because of the back-to-back S’s, and [name_u]Francis[/name_u] [name_m]Thomas[/name_m] because they end in the same sound.)
I love the name [name_m]Cormac[/name_m], but I really don’t like [name_u]Mickey[/name_u] as a nn (or a given name for that matter; [name_u]Mickey[/name_u] Mouse, take the [name_u]Mickey[/name_u] out, etc). I also really like [name_u]Sullivan[/name_u] and think [name_u]Sully[/name_u] is a great nn!
[name_u]Sullivan[/name_u] [name_m]Thomas[/name_m] sounds the best to my ear.