by Liberi Gothica Games
I am always delighted to see honest and open transparency in a project like this. I have been supporting kickstarters for a long time, and many even individual producers will obscure their costs and expenses, and wont be quite so open ended on the problems and how they worked to resolve them.
You have put out a great product that is hilarious and well designed.
That being said....don't feel bad if you have to merge a number of your small supplemental books into a single package. Also don't feel forced to pay for cover art for your extra material. A lot of this sort of material never really gets a cover art page, but as long as its good people will still gladly pay for it. If you then make enough of a profit that you want to buy and add cover art to it you can do that and then upload a newer version with the cover page.
Also depending on the content consider the Fate Toolkit. It is a collection of various resources all mashed together with a single cover page, even if these are separate bits of setting material it could be worth mashing them together into a larger single sourcebook unless you feel that would bring the overall product into a higher price range than you want to set each individual addon at.