I already see...nothing. The closest match I can possibly give you is Regice.
It fit all your criteria besides the last one:
- No Ice type Pokemon resists Rock or Steel. Because even with a dual type, the Ice typing makes the incoming attack neutral at best.
- Froslass is immune to Fighting, but it can't too many hits.
- The only Dark type resists are Weavile and Sneasel, which are both physical Attackers and cannot wall for life.
Regice has base 80 HP, 100 Def, 200 SDef, and 100 SAtk. Good bulk to take hits, and workable Special Attack. It can hit Steel, Rock, and Dark Pokemon with Focus Blast. You have to resort to Hidden Power [Psychic] / Hidden Power [Flying] in order to hit Fighting Pokemon. I reccomend the latter.
Another option you have is Rotom-F. It has a lame base 50 HP stat, 107 Def / SDef, and 105 SAtk. Better offenses, but the drop of bulk compared to Regice is quite noticeable. Hail can be used for Blizzard accuracy increase, but HP Ice can be used. HP Fighting can be used with Blizzard to hit 3 of the types you wanted to hit.
