Hi!
When I saw the page for Thorns of War, I was ecstatic because I enjoyed TRoS a lot due to the variety of love interests and the fact you could customize the protagonist's personality.
But when I played the demo for BFF. The concept was intriguing because there are very few VNs where you can have a major influence on another character's development and love life (and the protagonist's a ghost, that's rad). I'd be happy with supporting both games, although I must confess that I'm not a big fan of Kickstarter and crowdfunding in general, but I would put money down on Thorns of War.
For marketing, have you tried posting onto Reddit's r/otomegames community? They are a very welcoming community and I believe TRoS and Heaven's Grave have been well-received by the users there.
(Heck, someone linked to your survey in that subreddit a day ago)
You could also try posting on r/visualnovels as well but they aren't as friendly to OELVNs compared to r/otomegames, unfortunately. (Well, it depends on how you advertise it. From my observations, general quality, genre, artstyle, whether it's an eroge or not, and whether it's bishoujo or otome, yuri or BL, or features no romance at all are big influences in how many upvotes it gets.) Up to you whether you want to post there or not.
I'll be eager to see which game comes out on top in the survey, and good luck with the Kickstarter!