FO Full Zeta Squad -- Who/When to replace?

FOST/krum double tank with ogkylo and FOX is a TM machine (not up to zzEP level, but still excellent). KRUM will pass out advantage every time he's damaged, and spamming ogkylo's aoe will give 50% TM to everyone with advantage, while possibly resetting his CD's at the same time. FOST's zeta will spread ten down, healing immunity, DoT, and stack FOX's Max health ( from his unique) at a very fast pace, along with the TM to the assisting toons ( from KRUM lead ). It all stacks up really fast with krum/kylo/fox/fost. The 5th should be either FOO or FOSF ideally, since fotp is just too damn squishy. Fox will build up his health quickly enough that he isn't squishy for long, and you can actually afford to use a health primary on his circle, triangle, and cross, instead of a CC triangle or offense because of his unique boosting his offense based on his Max health. Crit chance isn't really needed with him, since he will almost always have advantage and his basic always scores a crit against debuffed enemies.

https://swgoh.gg/u/brakir/collection/?f=first-order

For DSTB, I always use krum/kylo/fox/foo/fost and haven't dropped any waves with them yet.
For tw, I use them on defense running krum/fost/fox/kylo/zarris. It sounds strange to use her, but that squad has insane Regen capability against everything except top meta teams, and the abilities are so well idiot-proof that the AI won't screw it up like it will if you use fotp/foo/fosf as the 5th. They haven't been taken 1:1 yet since I finished taking them to g12.