That is a really great lineup you have planned, and certainly better than what I had to work with when I first started using my Batman. Earlier on, where you are at now, it makes sense to pair with other leads, and Neph is, as you say, a great option for the bulk. Later on though, you will probably want to focus on pairing with other Batman leads, as cross-pairing becomes less useful. Like, to the point where I will use Batman exclusively for normal alt coin dungeons, but prefer a different team for the no-dupe ones, because at higher levels of play pairing with a different lead kind of dilutes his firepower, and if you can't hit hard enough you kind of tend to die. You can get quite far with the setup you have, once you have enough cost to evolve/awaken everything. My only suggestion would be, if you see the chance to roll for a Hanzo (3x rate ninja carnival that's paired with something else you want would be my suggestion), I'd strongly suggest trying for it, if you have the stones. Haku + Hanzo is a godly combination for killing bosses, as it gives you pretty much a perfect dark row board to work with, and max-skilled Hanzo is super useful, and in your case, having one of those and that valk max skilled would be...very powerful indeed. I don't have a Valk, but I recently got a second Hanzo and maxed skilled both while trying to skill my Haku in the watery temptress dungeon we had recently, and having two of 5 CD orb changers has let me do dungeons like Legendary Path I wasn't able to do before with just one.