All of those links take me to a page that requires login on aliexpress.

Is there any reason the official netgate solution wouldn't work for you?

I'm not sure if the SG-3100 would work for the home, office and guest setup using the LAN and OPT1 interfaces. Not sure if the RT-AC87u setup as an access point with a separate guest login would prevent the guest users from accessing the rest of the LAN it's connected to. My feeling is it wouldn't so you might need another interface and AP for the guest if that's the case (SG-5100).

If price is an issue, I hear good things about the apu2 platform.

@johnpoz When I installed pfSense on the new router I created two interfaces... I had read on the basic firewall page that OPT interfaces have no rules and forgot that - thanks for setting me straight and waking me up. Firewall rules are scary but I'm getting there.