Wow, we've spent way too long discussing Aura's statement that Belthasar was there for several years!

Personally I would believe that he was. Time-error would seem to suggest that. Take a look at the people who've been gated and the evidence surrounding them:
Janus - Gated as a child, and was in the middle ages for several years...had time to grow up. This is the most obvious one.
Gaspar - Gated to the End Of Time, and when you meet him the first time, the things he says suggest that he has been here for a long time... At least a few years. Although later, when his name is mentioned, he responds, "I believe that's what they used to call me...ages ago..." We are probably not meant to believe that Gaspar has literally been there for ages, but several years ("several" being enough for Janus to grow up) WOULD seem like ages if you're the only one around!
Melchior - Melchior has grown accustomed to life in the present: he mentions that he lives on the continent to the east (not "I'm new in town" or anything...it's like he's been living there for awhile), and the imps in Medina say that Melchior "lives" in the hut to the west... They don't say that he just popped out of their cabinet last month like you did 3 minutes ago... He's been there.
Given those 3, it's probably safe to assume that the last one gated from the Ocean Palace disaster, Belthasar, has likely also been in his new home for several years.