Out of place, but not by very much - at least with the Frostgrave and GW stuff: those seem to all mix-and-match really well between each other, in my experience.
The bodies are a bit small, I think, which makes the head and weapons look big, or at least even bigger than they already are!
I'm not a huge fan of the Oathmark human infantry, but for quick-and-dirty box of generic fantasy infantry (town guards, mercenaries, henchmen, etc.), and for a bunch of generic, uniform spare bits (plain swords, spears, and bows) to kitbash an army with or upgrade some Reaper Bones noodle-weapons with, they'll do.
Those conquistadors, on the other hand, are NICE. I'm definitely going to grab a box or two of those!
Wargames Atlantic would be my go-to choice for any fantasy human army now, between the Conquistadors, Irish, Goths, and Afghans.