A weather team does not need to have all Pokemon that benefit from the weather - particularly Hail where you'll leave yourself with a massive set of common weaknesses.
Ninetales and Sandslash are probably enough. Mega Abomasnow if you want more offense than support from Ninetales. Then you want Pokemon that can reliably kill Fire, Rock and Steel Pokemon - something like Garchomp is an excellent choice.
If you're concerned about taking weather damage, Pokemon with Magic Guard (Reuniclus, Alakazam), Overcoat (Escavalier, Mandibuzz, Kommo-o) can round out your team, or give anything the Safety Goggles. But remember you won't have Hail up all the time, so it isn't necessary to always be immune to it.
