Some of the comments in the thread about newbies off the RJ and such seem somewhat implausible. Admittedly speculation, but the kind of not-crisp, unfocused, younger-dialect of the PNF on the transmissions speaks presumably to him being not the CPT, which means the CPT is flying, which should mean he/she is not some newbie straight off the RJ, and should have sufficient knowledge of the aircraft and attention to anything tricky about transitions when that heavy. Which is why it's a bit of a head-scratcher to me.
Or maybe my premise is wrong and it was the CPT on the mic, distracted from communicating because he was focused on what the newbie PF was doing. I guess we'll eventually have a clue.
Most importantly, glad this ended well.