I'm against making a Patreon to solicit funds at an early stage like that - too many shitty games trying to do that. Perhaps we should do a free Patreon account? But even then, if only 10 people respond/participate in the poll, that's not gonna cut it. This website probably has the best feedback.
I was thinking:
1) maybe I should make a video of all the content and put it onto pornhub - maybe that gets some interest; and
2) maybe I should release it on Steam as free-to-play game? That will get me anonymous stats, but I have no idea if people actually do play these types of games on steam (they do allow nudity nowadays)
What do you guys think?
If a free Patreon (or possibly Subscribestar) account is a thing (I don't know if it is) then that might be a way to go. People like free stuff, so they might be more likely to subscribe to try the game and give you feedback there if they aren't shelling out on a paid subscription. You could do polls, bounce some ideas around to see what sticks etc, much like you can here, but potentially to a slightly different audience. Also, I know of some Patreon creators that sometimes do shoutouts on their pages to other creators' games on the site so that could get you some extra interest in the project.
As for the other options you've mentioned, putting a video up on Pornhub showing all of the content seems a bit redundant. A trailer of some kind might drum up some interest in the game but you likely won't get any meaningful feedback on the site from either of those 2 options.
With Steam I think you have to pay a fee to include your game on the platform before you even begin. People definitely play adult games on Steam, House Party, Being a Dik and several other porn games sell very well on the platform so there is a market, but they appeared on Steam later in the development cycle with far more content. Some devs have started their games on Itch.io instead, and have picked up feedback that way, and have then gone on to release them on Steam later on.
Whatever you decide on doing, good luck