VPS - IP options, reverse-dns, any obstructed services, deployment options. Any hints welcome.

Hi...

I'm considering a project requiring a tiny VPS (or hosted docker container) with at least 1 public IPV4 (with a specific reverse-DNS) and at least 1 public IPV6 address... minimal RAM, CPU and disk requirements – probably low network traffic too. 100Mbps would be plenty.  Once set up, I imagine keeping the VPS running long-term.

1. The "VPS Starter 1-2-20" looks adequate... but, when I configure it, I can't see options/info about IPV4/IPV6. Can I order with confidence that I'll get (at least) one public-facing IPV4 and one public-facing IPV6 address? Would I need to have done something special at configuration time?
2. How would reverse-DNS configuration (i.e. an entry mapping the public IP address back to a DNS name of my choosing) work?  (I already have facilities for 'forwards' DNS - to map vps.mydomain.org to the public IPs for the VPS.)
3. I'd be happy to pay up-front for up-to a few years... though this seems to preclude the (very generous) special offer - which seems restricted to a monthly no-obligation contract.
4. Is deployment using Open Virtualization Format (OVF) or docker images viable - or will I need to configure an OVH Linux instance?
5. I don't see support for Alpine Linux.  Am I overlooking something?
6. Are there any restrictions on protocols/ports/services it is legitimate to run on a VPS (obviously, I'm not intending anything illegal – or anything I consider controversial)?