@Godie 

Hi,

First point: That "EasyMesh in AP mode"-thing is only important for the "Main" router, if you want to use that router in access point mode. 
For the "Satellite" nodes it doesn't matter whether they support it or not.

Second point: That's the whole point of EasyMesh.

Third point: Depends what you mean by "manage the device in room 2 using the web console from the main node".
Certain settings are automatically being synchronized between all EasyMesh nodes when you adjust that setting for the Main node. But you cannot individually adjust settings of the Satellite node(s) via the Main node's web console. 
The web console of the Main node allows to view the firmware versions of the Satellite nodes and also allows to update the Satellite node's firmware.

As for the Ethernet backhaul connection via the ISP router. In this case the ISP router acts like a network switch. According to previous posts on this forum routing the Ethernet backhaul through a switch has worked fine for most users, however, a few users apparently had problem with such a setup.
 

  @woozle Thanks.

So if EasyMesh is basically to implement seamless roaming, does the setup I showed above support mesh features or is it basically a centrally managed setup to manage the 2 devices that only support seamless roaming between those devices?

Basically what I need is seamless roaming between access points connected to the ISP provided router via a network cable. I'm not sure I need "mesh" features in this setup.

  @Godie 

You can read here https://www.tp-link.com/en/easymesh/ what EasyMesh does. But it is not possible to have only parts of it. It's either EasyMesh=ON or EasyMesh=OFF.

  @Godie In the setup you described, does it support mesh features for seamless roaming between access points connected to the ISP-provided router via a network cable, or is it primarily a centrally managed setup to facilitate seamless roaming between only the two devices involved?

  @madera2 Hi, basically what I want is to have two TP-Link routers connected to the ISP provided router via network cable, both working in access point node and be able to do fast/seamless roaming between the two TP-Link routers. It seems that in order to enable fast/seamless roaming it requires a centrally managed setup with EasyMesh. According to what @woozle said above this should be possible but certain users have reported problems using this setup.