New Dave

Regurgitation (not puked) is a better word for what he is doing which is a very common behavior. I would make sure both birds are on antibiotics personally because the 1st one was sick and the 2nd one is getting sick. I don't think it was wise of the vet not to treat your new bird but that is only my opinion.

Fecal tests are not the expensive, did you ask the cost? I had it done on Merlin and it was very minimal. Now going into x-rays yes is costly.

Word of advice keep them very warm and calm until everyone is up to par and do not put anything in their cage that resembles a nest because a male and a female usually will not try to have a family if the cage is set up correctly. Example, no nesting boxes, no fluffy cozies to lay in that they sell at the store etc....