If it's any help, I used Deathwatch rules for my Marines in Kill Team '21 (they were actually 'regular' Chapter Astartes, but I wanted to capture a specialised, elite feel than the standard Tac Squad fire team*). I struggled to win games with them to be honest - they were kind of 'Jack of all Trades, Master of none'.    So if your concern is not taking an OP team that will stomp your friend's teams, I think you'll be fine with what you've got. Obviously, how you choose to play them in

Not a lot to add, but I must say that I love the use of the MkV character (am I right in remembering it was a World Eater?). I wouldn't have thought of such a brutal looking mini as a RG, but it really works well and the pose is great for adding a jump pack!    Really like the Seeker squad too!

I think (memory is a little bit fuzzy, and I'm potentially mixing up stuff from the latest edition...) the 'meta' DW team around that time included a Frag Cannon Heavy Gunner, a Plasma Gunner, a Fighter with TH/SS, Sgt with Xenophase Blade and 1 or 2 standard guys with Bolter/Power Sword. Most of the team were quite focused on either melee or shooting, rather than trying to balance the individual operatives. I think maybe(?) the Infernus got better later in the edition (or maybe the Frag Cannon