Not easy, congrats on some solid yellow heroes.
I probably can’t tell you for sure whom to lvl but maybe can help who not…
With this options I would say forget about Leonidas and justice, they are nice but nowhere near the rest. Also vivi, I would do a second prof before her.
I wouldn’t do ranvir if wu is already max. Yes he is a little bit better, but not 6 darts better (at least for me)
Bai and joon are also relative similar so would probably look for little bit more diversity.
Between guin and neith I would rather tend to neith. One only cuts mana and give 3 heroes some heal, that’s on offense semi optimal, where neith also cuts mana, blinds them, damages them and has an element link. So if one of the two I would lean to neith.
Norns is pretty much useless for a mono team, but great for myth Titan. So if you value myth Titans a lot she should be considered, if you don’t and don’t want to change your mono system in the next future forget her.
Devana is good, great element link, useful for mono, useable minion counter, yellow dispel which is rare.
You are saying you want something for offense mono and talking about family bonus for ninjas, so I guess that’s for defense? Than I wouldn’t do Mica, for defense he is just meh. On the other hand if you want to play those Ninjas together on offense why not. And even for a yellow mono he is nice, because with 5 stones he can be some kind of live safer if the board goes dry.
I would probably do Mica and/or Devana. Norns if you change from mono, or for myth Titan.
Edit: good point from @Ruskin505, sif and Mica won’t work well together…