Trump isn't personally owner of any of his buildings? They are owned by the companies he has stock in. Plus the buildings aren't worth as much as those companies claim (let alone in a forced auction situation), which is another set of legal trouble Trump is facing right now.
But no doubt those buildings aren't actually owned by the Trump organizations, but instead owned by banks like Deutsche Bank, because Trump used them for his fraude schemes (allegedly).
Or would Trumps stock be converted into money somehow?
The Trump org owns buildings, and the Trump org is liable for the judgment.
Basically they’re going to seize and auction a bunch of buildings with his name on them, and when their auction values come up short, seize some more. Then when they run out, Trump org declares bankruptcy for the 4th time.
Bail is something you post to keep you out of jail you're already going to, it's not debtor's prison. And we do it all the time; when people can't post bail, they continue on to jail.
In this case the bond is because he's appealing a civil judgement that's been reached. This is different from a bail bond. He's not at risk of jail over this unless he gets in contempt of court.