Menel, I very much doubt that anything you have done here could get you into trouble. I have to say I am intrigued by why you are so agitated but I am sure that it is unnecessary. From what I have observed, The Tolkien Estate act if people do things which directly infringe copyright such as publishing CT's maps or publish defamatory things (not sure if defaming via the internet counts as transitory or fixed ie slander or libel and that uncertainty should not be interpreted by the legal beagles as a request for their opinion - at least of the billable variety
).
Much of the content of the Downs and the other "serious" Tolkien sites is effectively a continuous symposium on Tolkien as a writer. I am fairly sure academic discussion does not infringe copyright. If you print it off and sell it ..yes you would need permission to quote (BTW if you go to your library there will probably be a notice by the photocopier telling you about the amount of a work you are allowed to copy before you break the law... something as a student I occasionally was obliged to honour in the breach rather than the observance
).
The fact is we are developing the readership... people who liked the films are encouraged to read the books, those who have read the canon are pointed towards HoME, those of us who have HoME obsessively attempt to fill the gaps in completing the complete bibliography.
The other aspects of the Downs are not disrespectful.. tolerated if not approved of perhaps.
The Encyclopedia of Arda makes comprehensive use of the names etc and they are unofficial
cf this disclaimer
As for fan fic/RPG well I should think we are a long way down the list of targets if you look at some of the stuff out there..and if you are squeamish you may not
Finally, it will not be very fair on the people with whom you interacted if you systematically delete your posts. I do suggest you contact a mod/admin privately with your concerns before you take such a drastic step.