IMPS.
The spots are approximate. You have played with this partner before, but you do not have much in the way of agreements other than you are playing a simple 2/1 card. If it matters, there was a bit of a tank between X and XX.
What do you think of 3♦ bid? Would you bid 3♠ instead? If so, under what conditions would you bid ♦ first? In some partnerships, I have a meta agreement to always show the major if you will only get to bid once, but this was not one of these partnerships.
How strong of a hand should X and then bidding 3NT show? Is south too weak for this action?
What should XX show in this auction? Is south right to leave this in?