A couple of things for your consideration
- If you already have an NDI camera, think about camera controls if you start mixing vendors
- If that Panasonic is HDMI, not NDI, then beware mixing video source types as they will have differing latencies. Assuming audio coming from elsewhere, you may have a real challenge without an upper-end console to keep varies audio and video sources in sync?? or I could be way off base... but, you are definitely adding complexity when you start mixing video source connection technologies
As for the NDI bandwidth, depends on if NDI HX or not. 4K uncompressed NDI times 4 cameras... approaching 1GbE but probably okay if not a lot of other traffic other than upload livestream (assuming such is the plan)
With the Atem Mini Pro (if I recall correctly) is HDMI input only. And then the common setup is such that the OBS PC only see a single video feed from the Atem. So much less work for the PC. but you lose some flexibility from within OBS... so depends on what you are after/workflow as to whether such would work for you
Precision Mobiles are nice beasts (I had one recently) but almost any laptop will be subject to thermal throttling long before a corresponding desktop would be. so making sure laptop air vents are unobstructed is a must, and may possibly benefit from assistance (external fan with duct direct flow to air intake). But in my situation, it was better to get a tower PC and put it in closet with sound mixer, and run a single 50ft fiber optic DP MST cable to run 2 monitors, and an active USB cable for keyboard and mouse
Part of the 'it depends' answer in regards to sufficiency of a given computer comes from details like video filters (chromakeying) or certain audio plugin/filters, which can be CPU intensive. So, a given PC may handle what you mentioned, but start adding some other filters/effects, demanding app (like a browser), and you can push a (any workstation) system beyond its limits.
