Don,
1) You will need to email [email protected] and tell them your situation and ask for a dual-IP license
2) JBossIDE *used* to conflict with MyEclipse because we have integrated it in. But I believe with the most recent GA releases, we cleaned up any conflicts between them. It would be safer not to mix them, and you should be getting all the JBossIDE functionality from MyEclispe anyway (I could be wrong)
3) The rest of these should be fine, the only thing you need to watch out for with plugins like XMen, XMLBuddy, Lomboz, etc. is that there will probably be initial file association conflicts between those other editors and MyEclipse as we provide XML and JSP/HTML Editors. So if you are good about making sure which editor you are opening files with, you should be fine (ours are all named “MyEclipse <blah> Editor”)