So in case anyone was wondering, it's absolutely worth having a single and multi version of the same team. Old news to some but the Multiboost awakening is extremely powerful. It multiplies all that monster's stats by 1.5. That is absolutely ridiculous.
Example: Light Myr
There's a couple ways to build teams for her, TPA, Row, and Multi.
TPA relies on you getting very lucky with Wedding Satsuki, and Apocalypse, while Elia adds more TPA goodness. Very high single card damage on a good board but tough to maneuver orbs and make the cross without screwing up TPAs.
Row uses the more traditional Myr subs of Wukong and DQXQ with Awoken Venus usually being a skill carrier. Apoc and Saria are both welcome here but I believe Apoc gets the edge since he combos better off DQXQ and Saria is usually on Venus.
Multi adds a wrinkle. Baal and Unicorn Rider both have multiboost and skills that synergize well with either team, Baal being more Row focused and UR being more TPA focused. Both have low cooldown skills making them solid inheritance bases (UR being better at this). Baal brings a ton of rows, unbindability, and a buff that can bait a dispel buying you another turn. UR provides a couple TPAs and a guaranteed cross with her skill. In Multi her effective no plus ATK stat is ~2200. With them it's ~3000. Add in two TPAs and she hits like a freight train in multi.
So you have a couple choices here. In multi you can bring both, or the one more focused on your current team. For me I'd replace Venus with UR and Elia/Wedding Satsuki/Wukong for Baal. If you have DQXQ and Apoc you can get away with Baal as a single orb changer.
Baal is still a solid sub for a row focused Myr team and can live on it in single and multiplayer I think. UR's skill is perfect for Myr but her stats leave a lot on the table until multiboost. As a result if you don't play much multiplayer I'd say she's a great inherit skill but not a must have. She competes with Moogle and her ATK being > 1 means she'll actually contribute damage to the team but you lose out on Moogle's utility, depending on the dungeon it can be worth it.
For me my single player Myr teams look like this:
TPA
Myr (Snow White)
Wedding Satsuki (Saria)
Wukong (Gadius)
Elia (Cecil)
Apocalypse
I'll eventually pull gadius off Wukong and give him cecil but tans and coins are holding me back.
Row:
Myr (Snow White)
Baal (Ars Nova)
Awoken Venus (Awoken Yomi since Saria is on Wedding Satsuki)
Apocalpyse
Wukong (Gadius)
Multiplayer:
Myr (Snow White)
Baal (Ars Nova)
Unicorn Rider, Liene (Probably Wukong but nothing at present)
Apocalypse
Awoken Venus (Awoken Yomi)
Unless you need to really check your damage in multiplayer, that team is capable of putting out very impressive numbers with very little effort. When I hit rank 500 and got a new team slot this is what I put there. I don't multi with Myr often (unless it's with my alt) but when I do I'm very happy with the results.