Will any mangos grow true for seed? If so, what kind?
Answers:
Possibly, but they'll taste terrible... Mangos from supermarkets are hybridzed, grafted versions of an ancient fruit that did not taste very good.
There is one tree native to Thailands which is not grafted--I have no idea what its availability is, however.
Here is a fascinating read on the subject:
How can I bring my sun-burnt brown plants back to life?