Class: Dk, Warden, Necro. For race: nord, imperial, argonian, orc, redguard. When it comes to tanking any race can work fine as its the role where race matters the least.

Warden, templar, necro. Warden for buffs, templar for strong single target heals, necro for a strong debuff ult and rez ult. Necro may not heal as hard as templar or provide as many buffs as Warden but the major vulnerability ult is always sought after. Races: Breton, argonian, high elf, dark elf, khajiit. Breton for max mag and sustain, argonian for extra hp and extra heal and potion sustain, dark and high elf for spell damage and max mag, and khajiit for good base stats and recovery and crit.

Extremely highly situational. Any class can be strong in pvp if built right. Choose dk for tanky brawler, sorc for high mobility plus heals and recovery, nightblade for ganky stealth plays, templar for strong self heals and damage, warden for survivability and recovery. I haven't experimented with necro in pvp much but I've heard they can be hit or miss depending on your skill and build.