Nostalrius Begins - Quality wow vanilla realm (1.12)

Whats best for eu players. I like alliance. But don't know what class plz help.

I think alliance will dominate by population. Perhaps not by a large margin.

Any class that can use healing spells are in general considered to be healers (druid, priest, shaman and paladin)

only tanking class is warrior. Warriors can also do damage.

rogue, warlock, mage, hunter are the dps

If I were you I'd check how many guilds in EU go to each faction. I rolled Horde and joined a EU guild.