Asus 86U/68U mesh network with Firewalla blue plus

I currently have an Asus 86U access gateway meshed with 2 Asus 68U access points.  Asus firewall rules are very limited and I'm in need of more granular ways to block specific gaming and social media sites during school hours with my children.  I see in the compatibility that the Asus 86U is supported only in DHCP mode, which in turn, means it will have to assume my DHCP over my access gateway.  I just wanted to make sure of the following:

1. Will a mesh network work fine with installing the Firewalla Blue Plus off my access gateway to service my entire network?

2. I presume that with Firewalla device taking over DHCP, I'd have to re-IP all my IT devices like printers, ring pro, digital wireless cameras, etc?

3. With Firewalla, will it allow me to actively block unwanted gaming and social media sites for specific devices by MAC address'?  Mainly its for my daughter who does virtual schooling but not seeing what she's doing, I can only imaging whats going on behind the screen during the daytime.

Thanks so much for your insight if this is the right product for me to utilize with my Asus network.