Welcome to the game and congrats on pulling ME and PK.
The information you are looking for has been very well cataloged by a content creator named Deadwood Jedi. Go to his website: (https://www.deadwoodjedi.com/)
Familiarize yourself with his clan boss calculator: https://deadwoodjedi.info/cb
and most importantly, learn everything you need to know about your new "Budget Unkillable Team" here: https://www.deadwoodjedi.com/budget-unkillable-guide-by-1xavi2
I highly recommend you you Rahzin (Decrease Defense & Weaken debuffs), Nethril (Poison debuff) and Frozen Banshee (Poison).
Should be able to 2 key UNM with that setup.