And this, friends, is your regular reminder to have a backup system in place before the problems start.

The router will be great, you’ll have to upgrade the modem long before you have to deal with the router.

As for the modem, that’s probably the bare minimum I’d get to be confirmable saying it’d work for 2 people. I can’t find Comcast’s compatibility list in a quick glance, but Cox supports that modem on plans up to 250 Mbps - this will likely support you staying in the lowest tier for quite a while.

Faster speeds than that are only really useful for the impatient, who don’t want to wait for big downloads (like new games/updates), or for big families who do a ton of streaming. If you’re not anticipating either of those in the next 5 years, the $50 spent on that modem will not be lost.

LOL @ MSRP $18k. Hope OP is made of gold.

For OP, you may want to consider your 6-port approach, not much sense in putting cameras and a Raspberry Pi on a 10G switch unless you’ve just won the lottery and aren’t telling us. Otherwise that’s just a lot of commitment for “pretty”.

This one is extra tricky… The simplest thing you can do is get them set up with a browser ad blocker, and it wouldn’t hurt to get a simple pihole setup going for them as well, or point DNS on their system to a similar service with malware filter

I’m sure there are others out there with more expertise in this area, and there’s always more measures you can take, but that’s where I’d start to try and limit their exposure.

Another poster sent you an exhaustive list, but to answer your question a bit, AMD has been dominating in the performance/watt category for a while now, I’d consider a Ryzen processor. Anything made in the last few years will be more than robust for what you’re describing. Hell, if you’re willing to wait for delivery I bet a Raspberry Pi 5 could suffice