Thanks, any and all opinions welcome

That's exactly what I need, thanks! And yeah I'll probably go with that company, they seem to have great reviews and will answer questions

I just heard him talk about that the other day, that was from a wood burning fireplace with the flue closed. Unfortunate to happen, but the liner kit is pretty foolproof as far as how to connect things an where to seal them. I'm aware of requirements like sloping the vent upward

Reading around it sounds like it's quite DIY friendly. I have a little tuckpointing experience as well if necessary.

Yeah neither has a powered vent, they are natural draft. The clean out door on bottom seems adequate to fit a 5" liner but I was planning on feeding from the roof and have someone pull the rope from the bottom. Did you pull up from the bottom?

There's a clean out at the bottom and looking up from there, it appears that there's a void between the brick and clay. It's hard to see if there's any supports, but the bottom of the clay is just hanging at the bottom. I'm going to have to get a better look with a camera I think, but it's definitely not encased in mortar.