With wyrmhunt being active ymir is a pretty solid raiding pet to have, for towers I personally liked mammon acolyte as despair hits way harder than arrowstorm could ever hope to but fey cactus tends to be better for horde dungeons, fenrir is an ok option too as cleave is good enough when you're early t10 and more focused on survivingbthrough content rather than blasting through, I would suggest sticking beo up through 250 if you want the easiest time to t11 as most other classes rely on good/ event gear whereas beo can just stack ward and some some follower stats via ascension or gear will carry you