I've never played 5 card, but I'll give it a shot.

A) fold. a King and a jack both called, which limits longshot straights and plus if the king pairs on the river, even if you hit your queen or ten, you are likely to put in unnecessary bets on a losing hand. Same for the ten, since now you have 2 hands to compete with instead of 1. The suits don't matter much, straights and flushes are nice when they hit, but with only 5 cards total, the chances are not as good that you will get one of those.

2) If you can reraise to isolate the king, great. If he has kings in the hole, you need a 5 or to hit a second pair. You don't want 8 to stick around and get another card to bust your pair.

3) one of your outs is gone, and if you raise, the kings might see that and decide to race since they have a higher door card showing and the same number of outs for non paired cards. Not sure what I'd do, if I was playing this game I'd probably play alot of pairs, and high live cards, ace in the hole would be good, but since I got one less out, I might pass on it.