What can I answer you is your first question.
According to this thread, mounting with gem is allowed.
http://www.regnumonline.com.ar/forum...ad.php?t=95180
(See 7th and 8th post.)
To your second question, I think you probably know more than me
To your third, last time I saw, they are but no one is participating. True or not, I don't know.