Router – Two routers connected to a switch= same IP host address

I would use ESW card in router if I had small office that needs to have 5 users connected. Then I would have router and switch in same device instead of buying a separate 2960 or such.

The only benefit I see with using EHWIC card would be if you need to use LAN features like port security, private VLAN, DHCP snooping etc. However in the first case you mentioned you would use the router as pure router and leave switching features for a real switch.

So it boils down to if you want to have routing/switching in one device or multiple. The only real use case I see for it is small office that doesn't need 24-p switch. You would only need to manage one device as well.

The HP can be either a bridge or AP, not both.

I recommend that you do this: just replace the HP with the Netgear, since it can handle more clients than the HP. If your wifi signal is good enough to cover the entire ares, that might be the simplest option.

You also might consider using both: put the Netgear in the same location as the HP. Connect the Netgear wired port to the HP. Use the DHCP server on the HP. Set the HP and Netgear to be on different channels (eg, 1 and 11). You can either use the same SSID or differnt ones, but the idea is that half your clients will connect to the HP and half to the Netgear.