Wow sorry to hear that, I had no idea the studio was having problems. Thank you for being so open. As fans of your work I hope we can give you some ideas. Marketing is definitely important. I'm not much of a social media person myself but I work in a company and know it's vital for the sales. My suggestion is to put your game out in sites like https://www.englishotomegames.net/ me and many other otome fans visit sites like those. Maybe make a tumblr page and a DeviantArt page? You could get word out that way.
As of Kickstarters, I don't really know what people are wary of, I've backed many projects in there and would happily back Bff and thorns of war. As far as rewards go, exclusive wallpaper, digital icons etc. are good rewards for starters. I like the plot of both games, being a fan of high school themed games (Makes me wish I had that romance when I was in high school) and Victorian era themed (I love movies like Pride and prejudice and the way things used to be in that era.)
I've played Heaven's grave. (I won it :D) I liked the game, the writing was amazing! I love the way people talked in those times, you're writing was very time accurate. As of now I've only played Suiza, as that's the type I usually go for. And I enjoyed his route, their banters and relationship and how he developed as a character. My only complaint would be that I didn't feel they had all that many romantic scenes. I don't even remember the protagonist thinking she had feelings for him, I understand the world is ending but it would still be nice to see her even be attracted to him. So it was kind of surprising to hear her say I love you to him after he kissed her at the end(Spoiler oops.) The romance felt rushed at the end, the game focused too much on the plot of the world ending and did not focus on their romance, at least in my opinion. I'm hoping to see more romance on the other games. The romance was also lacking a bit on Rose of Segunda but it was smaller compared to Heaven's grave. I hope it gets expanded on the sequel.
But nevertheless I love all your games! I've played all of your games and will continue playing all the ones to come. I hope you don't give up or postpone BFF or thorns of war, they both seem like good games. Also maybe you should ask other devs on what they do? I'm sure they can give you tips. I'm not a dev so that's all I can tell you as an otome player. But I wish you the best of luck! Don't give up!