So yes, FTP Cat cable works fine for the analog XLR boxes. FTP, as you might know, has a foil shield over all four twisted pair along with a drain wire that is, typically, the solder point for the shield. Of course, the RJ45 connectors must be shielded as well. I physically solder the drain wire to the RJ45 for a secure connection although there are You Tubes on how to make that connection when you crimp the RJ45 onto the cable.

I recommend stranded Cat cable over solid if you are using it for location work; much better handling and coiling.

The Neutrik Ethercon connectors work well; I use them wherever I can in my rig. They have some series that will fit onto pre-made cables, but that involves a split strain relief which I don't like. I use these:

Neutrik NE8MX-B-1 Ethercon Cable Connector Black Chromium Housing

These only work on DIY construction.

But I build all my own ethernet cables; way cheaper than pre-made if you need a lot of cables. But special tools are needed and there is a learning curve involved.

D.