I guess the main issue with having specific searching for characters of a specific orientation or w/e is that Toyhouse literally does not have any mandatory informational fields about your character (other than creator/designer and name). TH doesn't require you to put orientation or gender on a character's profile, they leave the entire profile of your character up to you. If you want to put the orientation on the character, it's your choice.
So the issue would become that to have a search feature like this work, TH needs to put mandatory information sections in all characters. People could ofc leave them blank, but then what's the point? You can search by tag and keywords in character descriptions already (the search feature at the bottom of the page). While not great for seeking RPs, Toyhouse isn't really a site geared towards that. A tweaking of the RP forums could be helpful but I don't think it'd be a good idea to enforce these parameters on all characters just so that an RP search works. The best thing TH can do is to just let you search certain terms and tags.... which it already does. Not everyone uses the "basic fields" function. Not everyone uses tags, or folders. TH is unique in that it lets you set up your account and characters literally any way you please, which I think is a huge draw to the site - you make everything about them your own and there's no parameters that already exist that you are obligated to fill out. You choose.
On top of that, not everyone on Toyhouse is seeking RP. So they could fill in the information about gender and sexuality and whatnot, but then be annoyed by the influx of people asking to RP. People already use the Worlds subforum to seek RP and while it's a bit inefficient, I think an overhaul of the system would be more helpful than this. And even then, you could honestly just manage it yourself. A good chunk of TH is self-moderated and self-sustaining. Nothing is stopping you from making a masterthread where people can fill out these parameters (orientation, gender, etc) and then seek RP partners that way.
EDIT: also I'm already mildly annoyed that people can see when I last logged in; I definitely do not want people to be able to see if I'm "online" or not. There's a reason I'm always invisible on Discord.