As for Vegeta's statement on 2nd form Freeza, I dunno if someone has brought it before, but I don't think it inherently means 1st form Freeza couldn't control his battle power... right before powering up Freeza stated how he can't control his power well in that form, so Vegeta might just be surprised that Freeza in his 2nd form can control his battle power as well, as in "so he is capable of controlling his battle power in this form, that he had previously stated it's hard to control?". That is, Vegeta saw how 1st form Freeza could control his battle power, but still wasn't sure that Freeza in his 2nd form could do the same.
It's either that, or what Freeza did in his 1st form was akin to what Vegeta and Nappa did on Earth, where the Z warriors' reactions clearly implied they were changing their battle power, yet they couldn't really change it... dunno.