You said he already looked sick and then with the added stress of being moved to a new place( and such a big one) could be what caused the regurge and also what caused his death. 29 or 30 gallon tanks are too big for babies. If you offer enough cover as Mindibun suggested, then it would help.

You should definitely be able to tell the difference between poop and regurge. Regurge looks like an undigested mouse/rat and they smell pretty bad(worse than poop).