Can you explain a bit more your concern around firewall and remote access? Is this a property that you don't live on that you'll be absent from most of the time? If not, I would not worry too much about it. You can put the whole darn thing on a dedicated internal LAN with no internet access if you want, but even that's probably overkill for most home setups.

Motion tracking cameras, especially PTZ auto tracking are mostly VERY expensive from what I've read and not as great as you'd hope. Motion sensing is pretty common anymore, usually done in software.

I found the sweet spot right now to be a combination of something like BlueIris if you're going the PC route and hikvision or similar cameras. You can get a pretty kick butt system for a relatively small cash layout, and there is great community support, which is even more valuable.