I am just really curious about MNM, about where its at regarding the beta, i think you said that it would be released on steam as a beta too? It's been quite a long time now since I played MNM and will probably have to replay it at some point, but it would probably help a lot if I just waited for the beta to appear on steam.
Also regarding MNF I think as long as you can keep adding girls and coming up with stuff like you did with lucy, you could probably go on as long as you were able to.
I really like MNF its easily one of the best vn's out there at the moment, well i mean ive played he hundreds of vn's its easily in the top 3 for me. I just really like the girls you have created, in so much as their backgrounds and stories. Lucy and fiona are quite hard hitting background stories for those two girls, and the way they pull through and become much better people. i mean the reverse could easily have happened to either or both of them.
I just hope we are not going to come to the end of MNF any time soon, but I would sadly understand if you didn't have no choice, due to lack of ideas etc and your health which is far more important than any game your creating.
You need to do whats best for you and your mental health regarding where you go from here. I fully support whatever decision you make even if it might not be to my liking.