Yes, if the Nord select dominion as faction he will end up in Auridon.
Note that with one Tamriel he can go there anyway but might be locked out the dominion faction quest and probably guild quests.
Dominion also only have only one starting island not two its an larger island with Khajiit.
Khanari's Roost is the Dominon starting island I believe but by default in One Tamriel do you still go to the starting islands? I thought you now come to the mainland right away and traveling to the starter island is optional if you talk to the npc by the docks
I don't always drink Skooma, but when I do I go to the Southwall Corner Club. May you walk on warm sands my friends.
It was changed already during or after beta so you end up in Ardudin first instead. A shame as Khanari's Roost is very nice.
The other starting islands is a bit small.
With One Tamriel they changed it back so you start on the starter island after leaving the Wailing Prison.
And yes, any Dominion-affiliated character will start out in Dominion territory and be considered a Dominion character, regardless of the character's race.
With One Tamriel you can actually play the zone quests in any order you want. The only PvE things that will force you back to your home alliance are the Harborage quests and maybe Fighters and Mages Guild quests.
If your Nord friend was dropped off in Bleakrock after leaving the Wailing Prison, then I'd verify whether he definitively chose Aldmeri Dominion as his alliance when he made the character.
Even if he's technically an EP character, though, you can still quest together through the AD zones.