who was the last cruiserweight champion in the wwe?
BQ: who was the general manager that put a freeze on the cruiserweight championship belt that led to it being discontinued?
BQ2: what was the reason given for taking the title at that time?
Well Andrew D already got the answer. Hornswoggle was the last cruiserweight champion.
However, I'm not sure if its intentional, but your BQ can be a trick question. Although it was Vickie Guerrero who stripped Hornswoggle of the title, she was only the "acting general manager" of smackdown, so she wasn't technically the general manager. It was still Teddy Long who was still GM, but out due to "injury", and Vickie was the one that stripped him of the belt, but she wasn't technically GM. So the truth is, it might be no one, but Vickie is the person that putted an end to the crusierweight belt.
As for your BQ2: I don't know the technical reason why they took that title away other then having a chance to spread the cruisierweight division on Raw and ECW, and not just Smackdown, but the storyline was that because Hornswoggle was the illegitimate son of Vince McMahon, and due to his stature and sudden wealth, he was an easy target for guys like Jamie Noble (who he was feuding with at the time). So for his safety, VickIE Guerrero stripped him of his title.