The drawback of solid wire is the difficulty of bending it behind a normal thickness wall without putting a lot of strain on the connectors. Flexible is better if you're going to move (i.e. flex) the wire occasionally.
The video guy should come up with a reason to use whatever he chooses, something better than "he thinks." And hey, run it by us! He might come up with reasons we've never thought of.
Definitely use 75 ohm connectors everywhere.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
