[Suzerain of Sheol]

It probably won't be a very helpful answer, but I think really it would come down to how you personally handled it. It's easy to imagine ways that those inclusions could seem tacky or strange, but that doesn't mean that they necessarily have to be at all. A large part of it for me would be the style of the narrative; if it sounds like there's a storyteller with a real personality describing things, I wouldn't think twice seeing a reference like that. In a more distant narration, though, it might stand out to a greater degree.

But, that avoids the issue of those terms actually being used in the setting itself, as in character dialogue, which I really think could be tolerable as long as it sounds natural. Reactions will probably vary on a case-by-case basis, too.

I am not hugely a fan of stand-in countries in secondary world fiction, though. It feels somewhat shallow, when even a mix of historical cultures with no additional creative invention on the author's part would be more interesting, generally.

Then there's the Traitor Son Cycle where it's literally medieval Europe except with monsters and magic, and the map is all wrong and all the countries have pretentious Ye Olde names (Alba and Galle for England and France, and so on.) but everyone is in on the con from page 1 being that it opens with a company of knights fighting a wyvern with Hermetical magic while swearing by "Jesu Christo". And really, what more can you ask for? :P