What are the best practices for VBS in multiple instance?

Summary:

We now have VBS in multiple lower instances. Could you please guide what should be the best practices?

(i) My assumption is we should have a single project across all instances. We will be able to access the same GIT from multiple instances. Please confirm.

(ii) We can have multiple branches which has our feature specific codes. This will ensure that all features are isolated which will help to selectively migrate only those branches using pipelines which are ready to deploy.

(iii) The only benefit which I see of having multiple VBS instance is that let's say TEST instance (which originally had the VBS) is on 24C but prod is on 24B. In that case, we can use another instance say DEVx which is also on 24B to migrate our change to production. Without multiple instance we cannot migrate from TEST to prod unless prod is also on 24C.