switch2osm tile server. What's next...

I was install Virtualbox conatiner with Ubuntu 18.04 and setup tile server, described here: https://switch2osm.org/manually-building-a-tile-server-18-04-lts/. Also i install Kosmtik to the same system. So, i can edit manually *.mss files and look at changes that regenerate Kosmtik for me. That is not very user-friendly editor mode, but i cannot find other possibilities.
I have some questions:

  1. For example, if I want to setup OSM-Bright style, i must create another database, import PBF to it, change some parameters with style, add new style section to renderd.conf and restart apache with renderd. Is it right?
  2. There is no compatible database structures along different style projects, it uses *.lua and *.style config files for correct import, and because of it i must import PBF every time in different databases per CartoCSS project. Is it right?
  3. Is there open-source or free to use render servers for vector styles? How to setup vector-tile server with manual import PBF data to it?