Jack has brought Castiel back before. But I don't see Castiel willingly sacrificing Jack.

That being said, if Jack could recreate heaven, I wish he could also recreate The Empty. Or allow angels their own heaven after they on. Castiel and some of the Angels deserved much better.

Castiel has outright said he's indifferent to sexuality. And k1lled a homophobic pastor to spite his false teachings. There was stuff liked that engrained in to Cass's arc from earlier on up to the point they basically adopt a son together which changes everything. The parallels, Charlie losing her lover, of Sam losing Eileen and then Dean losing Castiel, and before that, Castiel telling him "You want to know what's real about this? Us."

Angels are genderless, Dean called Zachariah junkless as a joke.

Ntm Castiel used a female vessel in the past. If he did, you can guarantee Dean would have had s3x with him at least once.

Castiel's confession was romantic, as confirmed by Misha, but Cass specifically reiterates "What I want I can't have" which means it's most likely unrequited. It's not in the having. Just being by Dean's side was enough for Cass to find his happiness.

Romance in supernatural has always been really quick to develop, like with Lisa, and Cassie, and April and Eileen, and half the other chicks but y'all only care when it's two people of the same gender, like Charlie being lesbian or Claire having feelings for Kaia.

Castiel is neither straight nor gay. Because again his true form is genderless.

And Chuck or God himself said he had taken a few boyfriends and girlfriends.

The angels are probably bi if anything. Thus Supernatural has always been a little bit gay and inclusive.

Dean doesn't have to return Cass's feelings for them to be valid.

Cass said what he wanted he couldn't have, it was unrequited love. Just being by Dean's side was enough for him.

Misha confirmed it was a romantic confession.