• install on bungeecord and every server on network, connect all to one database?
• or install only on bungeecord?
• or install on bungeecord and every server on network, but only config in bungeecord has connect to database?

Only on Bungee

if i have multiple bungeecord (redis bungee), so connect in to one database work?
i mean does this plugin support redisbungee?

I guess no, because it caches it locally.

i mean "one MySQL database", not SQLi. i gues it work?

Yes, but ChangeSkin caches it in memory.

Update to support multiple BungeeCord will coming soon. I'm currently working on massive refactoring to support it. It's be released after intense testing. So you can expect it within the next three days.

Sorry for the big delay. I was too busy.

Thank, i cant wait for this! :)