Looks like you are making progress developing your campaigns.
Here are my best answers to your questions:
1. Voice mail box full -- this is NOT a condition that POM can detect. Once the EP call classification has recognized that the call was answered by an answering device, it stops. Therefore there is no reliable method to determine "mail box full." One indication could be that the answering device hung up before the voice message was completely played out. That would require that the VoiceXML application delivering the answering machine message could detect far end disconnect and set a completion code to indicate this. For example, you could look at our INI OutboundStudio product on the DevConnect Marketplace. However, this is at best an indication. If the call classification was wrong and a person answered then simply hung up, that would trigger this behavior. Alternatively, if the answering device played a "Mail box full" message but waited for POM to hang up, you wouldn't get an indication different from having successfully left the message. The only way to reliably determine this condition is to have a person listening and doing the classification. If your campaign was preview, your agents would have to listen to this and could then set an appropriate completion code.
2. Phone number disconnected -- this is one of a number of conditions that are flagged under the Special Information Tone (SIT) category. POM's call classification should flag when it encounters a SIT but all POM knows and reports via a system completion code is SIT. It will not discriminate the specific condition. That is probably adequate for what you are trying to do, but it doesn't discriminate your two examples -- "call can't be completed as dialed" vs "the phone number has been disconnected."
3. Contact Strategy min/max agent configuration -- The min/max agent configuration pertains to the whole campaign. When you run a campaign, POM considers it in the context of what else is going on. Since you have a fixed number of agents, call it N, and possibly several campaigns running, POM first allocates agents to each of the running campaigns until they all have their MIN agent count. If the MIN values add up to more than N, then some campaign will not be able to run until its MIN number of agents are available. Assuming that the sum of the MIN values for the running campaigns is less than N, then POM allocates the remaining agents among the running campaigns based on campaign priority and probably a couple of other variables (see the user doc) until all agents are allocated or a campaign's MAX is reached. In a concrete example, suppose there are two campaigns A & B. A needs 5 agents MIN and only allows 10 agents MAX. B needs 3 agents MIN but allows 20 agents MAX. If A & B are both started, POM will allocate 10 agents to A (more than MIN of 5 but no more than MAX of 10) and 10 agents to B (more than MIN of 3 and the remaining 7 agents which doesn't quite hit the MAX of 13). Final comment: Yes, the user documentation has a tendency to tell you WHAT without sufficient description of WHY. We are continually giving the Avaya POM development team feedback on these things.