I really like Vincent! It’s definitely handsome and strong while still a little cheeky.
I think it’s only downside - and this applies to Eloise, Alice & Mavis - is the S sounding ending of Vince and the C (S sound) in the name, which is a slight tongue twister with your last name. I’m not sure how much I would tailor the name to your last one because as you say it (like my husband’s last) is just trickier to say than most (it’s a very authoritative, regal sounding, GoT style name though!).
I like all the names you’re thinking of, Alice & August / Gus are the trickiest to say, I think, with St@nislaw.
Other thoughts:
Jack (not as common these days and flows well)
Leo
Felix
Lucien
Gabe / Gabriel
Florian
Tristan
Roman (I like that suggestion!)
Julian
Philip
Marcus
Alexander
Sebastian
Dominic
Westley (I slightly prefer to Wesley)
Frederick
Quentin
Edmund
Murphy
Evander
(Henry does actually sound great with your last name but it’s very popular anyway)
Ruby
Zoe
Julia
Lydia
Leonora
Isabella
Josephine
Lucinda
Tabitha
Valerie
Lavinia
Marianna
Theodora
Evangelina
Willamina / Wilhelmina