Should I roll for Enkidu and does Merlin works well with him?

Yes. I consider Enkidu is quite synergistic well with Merlin. But not really recommended to make a specific roll.

It is indeed really hard to find a good team for Enkidu (except solo or dual Enkidu). I think his NP is most effective way to deal damage. And, we need a specific round for his critical NP-x-x brave chain. Therefore I made a critical team for him, but this critical team is to utilize his A-Q card for doubled NP gain in order to np spam.
That is why Merlin is still synergistic to Enkidu.
(1) Enkidu rely on both star and NP gain, Merlin is quite good in such area.
(2) Enkidu's major source for damage is his NP-x-x critical brave chain. In that turn, Merlin can activate his 3rd skill to maximum Enkidu's damage.
(3) Enkidu's 3 quick cards deck is a kind a burden in most circumstances, but in such critical team with Merlin, it is in fact good to even provide star for Merlin's art card for NP spam. It is a win-win snowball effect. If you manage well, you can easily obtain >30 star per each turn and trigger NP spam for all 3 servants on ground.

Overall, I am not particularity recommend Merlin+Enkidu combo, since you already have lancers, and Merlin's OP can be applied on other Buster-oriented DPS. But if make a team of him with Merlin, it is good.

Merlin works better with Tamamo and Kiyo than Enkidu tbh. I wouldn't roll.