Is holdo worth leveling for p1 JTR team?

Don't replace Trooper, he's one of your big damage dealers. I'm not sure exactly where he gets health steal (I'm guessing higher gear levels) but at some point he should be able to survive to enrage. Mine's G12 but I think he was fine at G11 IIRC. BB8 and R2 tend to be the biggest problems, even if you don't give them the shield, because they will die from AOE. I've had the most luck when I use R2 smokescreen to give himself foresight, and BB8 gets foresight from JTR's assist call (which you should be doing anyway with BB8's assist zeta). It takes a lot of tries sometimes though because the timing (and who gets the shield) is critical. Down the road, BB8's second zeta can also help suitability, as can giving either or both a G12 multitool (it gives added health steal).

Holdo probably will help you survive more but your max damage will go way down. Another option is Visas, but probably same issue. I know some people swear by Visas though.