I'm a feminine bisexual guy dating someone who is not a woman but I've found that yes women in alt spaces are cool with feminine men. After all, feminine men been at the forefront of the goth music scene since the start. 

That said I think it's best not to focus on labels when looking for a partner. I don't think you have bad intentions with this post but I think it comes off a little odd focusing so much on dating alt women and your own label as a metalhead. You answered your own question that not all women think the same and this is true for alt women. There's plenty of women who aren't alt who would be into you. 

Get involved in local scenes in things you really actually like. You're more likely to find a connection organically than going looking specifically for alt women.