[Questions] - [help]: how to config turnserver.conf for this use case?

Hi experts, Im newbie in WebRTC, but as far as I understood, in order to communicate 2 agents in different networks I should use coturn, as suggested by pairdrop (kinda airdrop, but multiplatform http://github.com/schlagmichdoch/PairDrop).

Now, the case is:

• fake Public IP (in fact, fake, because is behind CGNAT): 181.186.20.66
• real Public IP: 100.125.188.144
• Home router: port forwarding from fake public IP to internal Reverse proxy
• Reverse Proxy (npm) running on docker as container: 10.0.0.250 ports 80 & 443
• PairDrop Server running on docker as container: 10.0.0.250:9100 mapped in RP to fqdn: drop.micasa.ar
• Coturn running running on docker as container: 10.0.0.250:3478
• server name: srv1
• domain name: micasa.ar

Traffic Flows: (need to communicate to each others)

1. Agent A and Agent C, both in the same internal network, no NAT, no need to use TURN/STUN. [green agents]
2. Agent A (on internal network) and Agent B (on mobile network), so in this case TURN/STUN has to be used to enable peer to peer flow. [green agent vs. pink agent]

My questions: (coming from turnserver.conf)

• what should be my realm name?
• what should be my server name?
• what should be my listening IP?
• what should be my public IP?
• should I have a relay address? or not needed?
• should I have a leg into DMZ or direct exposed to internet?
• if no, should I have a port forwarding for STUN/TURN ports in my home router?
• should it work behind CGNAT?
• How to test this environment?

Sorry, too much questions, but no idea how to start with turnserver.conf ...

Thx a lot in advance!