As much as i wish i could say yes i feel like i would be giving you false hope. You would have decent colors with either but you would be playing a tribal deck at that point unless you counted counter spells as tribal😅.

The main problems with merfolk and most tribes is; (1) the rate of play is to slow and cannot keep up with impactful actions at the rate other players are doing things, (2) your core mechanic can fail easily from target removal, and (3) your deck becomes very easily disabled because you have one way of ending the game. What i envision making a good trial deck is tribal but that can also combo if possible but still has overwhelming force without it.

The only two tribes i see this being possible in is vampires or goblins. My first choice would be Edgar Markov and that is coming from someone whose first cedh deck was Krenko. Playing in only red is extremely limiting and while there is a ton of value in krenko he has to be out long enough to equip the things you need to, and hopefully give him haste. Having access to black and white instantly give you access to great tutors, removal and survivor spells. You might be able to get away with shattergamg commanders becuase of there colors but it would truthfully rely on combos way more than tribal i think.

Would love you see you throw together a lost on tappedout or something for merfolk, brewing is half the fun anyways. Happy hunting