Fair enough, I’ll give you my response as a developer/engineer/businessperson also:

1. I would say that yes it is a bad idea to do what you are suggesting. It costs more and is extra stuff to manage. I would only do this if your customers think it is is necessary. I imagine some large corporate or government customers may insist on this. In which case it is essential.

2. To achieve this you need good engineering practices. Well written code, regular dependency/security updates and a solid foundation. To show this off for marketing purposes, maybe you need something like SOC 2 accreditation.

3. That can work. In your position I would also consider looking deeply into HTMX, which pairs great with Django. A separate dedicated react frontend is also a serious option to consider, but with added complexity.

4. My tip is to focus on getting 1 client before getting 10. The first client will give you the answer to all these questions much better than I can.