Ferrothorn is still unobtainable if I remember correctly, and magnezone evolution can't be done till much later, possibly even later than in E15. however magneton is still excellent, especially with sturdy+thunderwave for some bosses.
solosis for reuniclus can't be obtained till magnezone can evolve, which is very late. however gardevoir works as a great psychic/fairy attacker and solid special wall with calm mind. misty terrian is also very helpful sometimes, but maybe a little cheesy i feel? you can get a ralts after you have 5 badges, explore the railnet for a corrupted pokeball if you want it.
Bisharp is very solid if it gets set up, but can be a bit slow and 4x fighting weakness can hurt. as you said, greninja gets dark, and magneton would have steel. mamoswine is really nice and adds two types you don't have, plus priority ice shard can be super handy, but he has enough speed to still go first a decent amount of the time without it. if you can breed one with icicle crash for when you need more power it's quite helpful. (ice fang is ok though) and if already breeding moves onto it, stealth rock is a nice bonus.