@Intense 

I think it is totally OK, it is a brand new product that tplink releases.

  @Intense 

Agree with @Virgo , as long as you aren't using the 7212 for extensive VPN tunnel/encryption its packet forwarding performance will be more than adequate for a 1G link.

You may want to be a little careful with your meshing (presumably to avoid wiring the 2 remote EAP655's).  Meshing uses the 5.8G band so any 5G clients (WiFi6) on those 3 APs will be competing with other clients trying to use the mesh backhaul radio link (meshed 5G clients double your traffic effectively on wireless connected APs).  In particular, 5G clients on the wired AP will be competing for bandwidth with ALL clients (2G and 5G) connected to the remote APs.

If you can find an alternate solution to backhaul from the remote APs (if not ethernet then powerline ethernet?) the solution will likely be more performant.

  @Intense 

Perfect!  So lock all your 2.4G radios to 20Mhz channel width and leave everything else on auto and you should be flying.

  @Intense 

I believe the guts of the all-in-one routers roughly correspond as below

ER605-->ER7212

ER7206-->ER8411

As I said, as long as you aren't doing crazy amounts of encryption, you should be fine.  If you want to be super sure, spend the extra $100 and the get the 8411