I have been working with Belial for months now. I don’t believe for a second that Belial intentionally changes people’s sexual orientation, especially for inane reasons, and when he’s said he won’t do it against their wishes. I believe that Belial’s influence or his energy perhaps, brings out what is already dormant in people. For example, you might believe you’re straight, but there may already some potential in you to be bi-curious/bisexual. I can see that being drawn out into the open via Belial. If there was zero potential for you to be anything other than straight, then it couldn’t happen. I think as far as these stories go, these people don’t really understand what’s going on with their sexuality, and don’t really get how influence works, so they tend to make up stories that make sense to them. Don’t be offended by that - it’s a normal - albeit bizarre - reaction, and it’s just how I perceive their stories. Belial is great to work with. If you feel ready to work with him, you should go for it - if you’re a bit concerned about his intensity, spirits can be mindful about sensitivities, so just ask him to be gentler with you.
As for possession - I’m currently in the middle of a pact with Lucifer which includes possession - you can agree the terms of the pact, including the degree of possession. For me this isn’t a complete possession as it’s not necessary for my purposes. I’m still able to make my own decisions, I can still conduct my daily life, etc.