EU regulators needs to hear from those affected to action, after march 7 they will take feedback

No, both manifest v2 and v3, but in earlier versions add-ons had to be vetted by reviewers or manually added to their account collections by users, but from v121,all extensions marked by their devs as compatible are available to everyone https://blog.mozilla.org/addons/2023/11/28/open-extensions-on-firefox-for-android-debut-december-14-but-you-can-get-a-sneak-peek-today/

This permission doesn't mean I can access your data for every site, this is an advantage of manifest v3

Firefox is stricter than chrome in manifest v3 that it provides no way to request host permissions at install time, there is a onboarding page after installation of addon where you can grant permissions to hosts

There is an onboarding step for permissions in firefox version(due to more restrictions in manifest v3 than even chrome),so you need to grant permissions, unstyled UI is intended but I will add style with a minimal ui css framework in near future

Libredirect is a manifest v2 extension (can't be published on chrome store) and has permissions for all_urls, predirect is a manifest v3 extension and only has permissions for necessary domains

Yeah I will add refreshable list of instances, custom lists probably not(extension stores has many restrictions on remote code loading)

It has a reasonable default of reliable privacy frontends but I may add an onboarding step(already in firefox due to more restrictions in their manifest v3 than chrome) for selecting sites

No, yes, It depends- for my simple use case of redirecting embeds and links, it is probably faster by using declarativenetapi instead of heavier webrequestblocking api