The $5.00 requirement pertains to marginability, not shorting. Institutional shorts don't work in margin accounts; most are hedging convertible notes at this point.
I have some CPN bought above $5 in my margin account, which presumably are loaned out. The shares I bought for less than $5 are in my cash account and can't be. As time goes by with the CPN shareprice under $5, margined shares available to retail shorters will continue to dwindle.
There are some very high risk short positions on cpn currently; hedge funds, brokerages, etc., can short anything they wish. The bashers on these boards, IMO, are daytraders(in and out the same day) and traders who follow the DJIA back and forth from 8000 to 9000 and vice versa. A few of the bashers are hired louts whose job it is to continually shake loose long shares to help protect the short positions. JMHO which is as worthless as any others here. Hehe Check cpn's website for the answer to your other questions