Before reading your list, suggesting my own:
[name_m]Ignatius[/name_m] [name_m]Aurelio[/name_m] [name_u]Valentine[/name_u] (seconding @tori101 Also loving her gorgeous suggestion of Fairfax!)
[name_m]Ignatius[/name_m] [name_u]Beck[/name_u] [name_u]Valentine[/name_u] (ooh, I quite like the snappy one syllable in the middle, even though it’s quite a style change! Beck’s my son’s name, I don’t think there’s anything about [name_m]Ignatius[/name_m] or [name_u]Valentine[/name_u] that called it to mind
)
[name_m]Ignatius[/name_m] [name_m]Conrad[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Luca[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Leo[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Henry[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Yves[/name_m] [name_u]Valentine[/name_u] - yeah, not great with a v ending going into a v beginning, so I’d swap to [name_m]Ignatius[/name_m] [name_u]Valentine[/name_u] [name_m]Yves[/name_m], but I do love the way it looks!
Of course last name may change everything, but I feel like with two three-syllable names, a name between with a different syllable count flows best.
I want to put something very sweet in the middle, perhaps…
[name_m]Ignatius[/name_m] [name_u]Remy[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Brodie[/name_m] [name_u]Valentine[/name_u]
[name_u]Or[/name_u] soft, like [name_m]Luai[/name_m], maybe to balance the strong G, N And V sounds in the other names.
[name_m]Ignatius[/name_m] [name_m]Ambrose[/name_m] [name_u]Valentine[/name_u]. Ok, this is my favourite that I could think of. Now to be inspired by reading your list.
I like [name_m]Endymion[/name_m], [name_u]Bowen[/name_u], [name_u]River[/name_u], [name_u]Atlas[/name_u], [name_m]Evander[/name_m] and [name_u]Jasper[/name_u] is my favourite! I think the flow of [name_m]Ignatius[/name_m] [name_u]Jasper[/name_u] [name_u]Valentine[/name_u] is stunning! 
I’ll suggest [name_u]Leander[/name_u], keeping the -er ending going into [name_u]Valentine[/name_u] which seems to work really well but avoiding the repeating V. I like alliteration but I think as the v is followed by a short a sound in both names here, it rhymes a bit too much? [name_m]Ignatius[/name_m] [name_m]Evron[/name_m] [name_u]Valentine[/name_u] works for me, for example. Although, I should not assume you are PN [name_u]Valentine[/name_u] the [name_f]English[/name_f] way. How are you PN it? Please correct me on anything else you need to
!
Some other -er choices:
[name_m]Ignatius[/name_m] [name_u]Archer[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Asier[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Bridger[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Bryer[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Xavier[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Harbor[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Kester[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Fletcher[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Thayer[/name_u] [name_u]Valentine[/name_u]
Taking inspo from some of the vibes in your list:
[name_m]Ignatius[/name_m] [name_u]Odysseus[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_u]Oberon[/name_u] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Theon[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Fabian[/name_m] [name_u]Valentine[/name_u]
[name_m]Ignatius[/name_m] [name_m]Ptolemy[/name_m] [name_u]Valentine[/name_u]