"Arguably"? No, they're absolutely necessary. It's a multi-tenant building. Why should my property and livelihood be threatened by your inability (or lack of desire) to follow the fire code?
"2. ADA compliant bathrooms and wheelchair ramps? Not part of a reasonable MVP[1]."
A reasonable MVP should include the ability for a social, interactive space to be inclusive. And sorry, it's not the same as a startup deciding what features to include in their initial launch (which arguably happened a long time ago - this, now, is when the details need to be nailed down). Oh, and the ADA is Federal Law, precisely because of businesses and such that felt that discriminating against a subset of the populace was an "acceptable" omission (for their "MVP" or otherwise).
"3. As for "building permits", they are just a tax by the local government"
That they are. Building permits are a method of more fairly distributing the cost of amenities and public services. You have ongoing property taxes for maintenance and upkeep, but a development may trigger a review - is water, power, sewage, traffic control, parking, adequate? Such reviews cost money. I'm confused though, how you then chose to quote an out-of-context example about "some" (unnamed) cities choosing to root out code violations - something not entirely the same, and actually largely designed to find people who have chosen to skirt their community obligations by not using the permit process.
For the record? I'm absolutely for the Hacker Dojo and wish more existed around here (and / or that I had the time / ability to found one).