The Imperial sword is a decent option. It kind of has an enlarged gladius look to it than any other weapon, like a more historically accurate spartan would use, but not from the movie 300. If things turn out good then the next expansion will have spears, that would be even more accurate. Imperial sword is probably as good as you are going to get, keep it sharpened as much as possible and you shouldn't need another one. Mods are the other option if you are a PC player.
That's very situational and is more personal preference. You could use a magicka-drain+magicka damage (fully perked, should take out around 70 magicka per swing), or a fully synergised flame-lightning sword (the damage should be around 169 damage without any perks in One handed or Smithing). I don't fight the Priests that often, and I try to fight them from a distance when I do because I can more easily dodge their spells. Also don't mind lanep, he's not the most patient person in the world.