Router for small business?

Looking at some of the Synology routers (like the RT2600ac). Low cost and Security are the most important factors. The business is a restaurant with up to 30 people and speeds will be limited/bottle necked by to the standard 30mbps cable broadband anyway.

Features I'm looking for:

• I don't necessarily need a router with an access point, if we can save money this way.
  • We currently have a AirTight C-75 Access Point. The manual / datasheet even provides radaition patterns, not typically seen on consumer level stuff! :D However it was configured from the previous owner of the business and we'll need to reset it. it seems we need a special UART/RS232 RJ-45 adapter to SSH into its console, although I have not looked into it too much yet.
• high degree of isolation between "guest" network and critical employee network (with Square POS, employee's BYOD's, NAS, inventory system, etc)
  • I like Steve Gibson's "3 dumb routers" solution, using the firewall of the routers to isolate threats between the networks. But would prefer one device rather than buying 3 junky routers that may lack support and have security vulnerabilities.
• Wireless isolation on guest network: Ideally each guest user will only see their device and the router. A potential hacker will not have be able to see or intercept traffic from other users on the guest network
  • Not sure if the C-75 mentioned above does this, we don't have the cable to play with the configuration of it.
  • Perhaps a "sign in" page? what would be required for doing what is often seen with Hotel WiFi?
• Features that enable bandwidth caps or a timeout
  • As a cafe, we tend to have our customers hang out at seating long after meals with laptops. It's unfair to other customers who then have no seating. So with a timeout feature we hope to encourage more movement.
• VPN capability
  • As the network admin, I might need remote access to the network at some point. :)
• All the other standard edge-router capabilities (NAT, ipv6, port forwarding, integrated switch and access point, etc)