escort TF will follow an ASW TF. Which if you are worried about subs, would be a good idea. Crippled ships enter into 'escort' TF, I believe it is a function of speed, IE if it is slowed to less than 75% of the TF speed, it forms an escort TF with an escort (if available).
Personally, I'd suggest having your cruiser escorts follow the Lexington, instead of in the same Escort TF, since you can keep the cruisers it 'mission' speed which will keep them safer from subs. Also, you probably want her to limp to the nearest major port, which sounds like pearl in this case, in order to get as much damage as possible fixed as quickly as possible. System damage affects a ship's ability to operate pumps, and if the pumps fail she can sink quickly.
What was the composition of the original TF? I try to keep a min of 6 DD with each CV TF, and then 2 more for each additional CV. So a 1 CV TF has 6 dd, 2 CV have 8, 3 CV have 10. I also try to keep 1 CA and 1 CL per CV for additional AA fire. Having 2 extra DD per CV allows me to detach a pair of DD to escort any damaged CV back to safety, and 2 DD in a hunter-killer group to lead the way. I also usually keep a few (4-6) DD at Pearl (or forward if I expect battle nearby) for emergency escort duty (always comes in handy).