He gets back his accords voice.
He may have had a larger voice under the Accords as Winter Knight than as a regional commander in the Wardens. He has status as a member or an Accorded Nation as Winter Knight. He'd have the same legal protections as Winter Knight as he did when he was just a member of the Council.
As consort to the defacto White Court ruler, I don't know if he would even be considered a member of an Accorded Nation. He'd probably be considered someone the White Court had a recognizable interest in, like the Council had in the women from WN. It's probably the same for the consort to the dejure White Court ruler, if/when that becomes relevant.
The protection the Council gave Harry wasn't a legal one so much as it was one of fear of retaliation. I think that protection was more important than any formal protections. It's that fear that probably saved Harry from being executed by the Council as a warlock. Fear of Mab and maybe even fear of Eb.
A lot of creatures that are said to be coming for Harry after he got kicked out of the Council probably foolishly are thinking of him being Winter Knight as Bob thought of the Knights in SK. As disposable as Dixie Cups. Just there to hold power. We know Mab didn't just want someone to hold the power of the Knight. She wanted Harry. I think anyone in the DF who was paying attention would have realized that. Therefore, Mab would have to react to someone killing Harry or lose face among those who had been paying attention.
Becoming Mr. Lara Raith will probably give him some to most of the protection of being in the Council back, but probably not all of it. It's probably his dumbest enemies who are only now looking for payback. Many of them will think of killing Lara's consort as only poaching and thus underestimate the likelihood and size of a response from the White Court. Those that get the importance of it as an alliance between the Winter and White Courts might not fear the White Court as they did the White Council. Other enemies might fear them more.