Just to make sure sure everything is setup correctly..
1. The internal IP of the Mac mini matches that of the ip in the port forward setup (10.0.0.22) Check via Utility-> Network Utility-> Info.
2. The Ports 3283, and 5900 are both open for the same internal ip address.
3. Confirmed that the Mac Mini is in fact running the specific static address you elected (Network Utility under Utilties)
4. Turned on Remote Management under Sharing Preferences (I also keep File Sharing turned on)
Also i remove all users from each sharing resource except the main user. For instance, "File Sharing" on my wife's Macbook Pro has only one authorized user, her with her system password. That way if someone was to try and connect remotely to her system they would need to either know her password or recieve it from her.
5. Go to "Preferences -> Security -> Firewall, and make sure it's turned off, at least during your troubleshooting. Mac's only allow you to define applications from the firewall menu, so if you do not have ARD installed on the MAC mini, but do have the Firewall on it may be what's causing your communication issues, just a thought.
The only other thing that is coming to mind right now, is turn off the "Disable Port Scan" security feature of your router, then while on the local network using your Mac go to Utilities -> Network Utility, then select "Port Scan" and input the internal IP Address of the Mac mini (10.0.0.22) uncheck the box "Only test ports between" leave it blank so that it checks all ports.
What you should see is your ports that you forwarded (3283 and 5900) assuming your router allows you to disable port scanning. If the ports are for whatever reason not getting opened you can turn apply DMZ to that address from within the router confing and then check for communication. The only other significant difference i can think of between your setup and mine is that you only have ARD running on one side, whereas i have it installed on my target machine. You could open up the App Store and login in as yourself and download the ARD App onto the Mac mini for free in hopes that, that may clear up some issue that has gone unseen.
HTH
-Brandon