How do you think they can they 'force' a conversion? The trustee decides what happens with PXUPA based wholly on their terms of issue, unless of course PPX and PXUPA all agree otherwise. As for buying out PPX and then converting by agreement - it would be a zero sum game. Anything they 'made' on one side would be lost on the other.
TLDR; the answers to your questions are 1. no and 2. no.
