I don't think Yeevia was serious, so lighten up. He just jokes and he knows you guys get your panties in a twist when he says things like that, so now it's just a natural response for him to give you a hard time.
No, no more veiltails in the world, but he could get a female to keep on the other side of the divider to be his friend. They like each others company and show off quite frequently to one another. What type of 5 gallon is it? They sell some pre-made dividers at the pet stores, or you could come up with your own using plastic mesh sheets for crafts like at Wal-Mart or Michael's. No, I don't think 2 bettas for that volume would be too much. You do not want to house them together though where they get to one another, they would and could kill one another.