Hi Bruno,
Is good to see you here as well :)
1) 7.0+. If you're in Windows only 32 bit is supported.
2) For RDBMS forget about DBXTalk and Garage, I would suggest you go straight to the PostgreSQL client (P3) or SQLite. Those are maintained and used, the rest... who knows.
If you need ORM you can use Glorp with any of those.
3) As Sven mentioned there are many options, there is people using Docker containers managed by Docker Swarm, so the options are many. But if you use Seaside with stateful sessions (you'll need affinity by session or IP).
Regards,