The first question, on target platforms, should probably accept multiple choices

Now when I think about it, true, but I guess people can just pick Other and list all that are applicable?

Quick sanity check. What does stack mean? Backend?

I guess it means different things to different people. I read it as “a collection of libraries”, that can be used to create an app/service. But re-reading that question and your question here, I can see that it isn’t clear. What do you propose?