Question about Netgear Ex6150-100pes

Theoretically yes practically better not (yes you can extender to extender but as said is not the best)

You have to consider that you lose time and speed per forwarding and there are more problems with the connection (interruptions).
I would not recommend more than 2 -3
Alternative: build an AP into your network if you have the possibility to connect it to a cable.

Hi. I have not had good experiences with extenders (interruptions, speed etc.) In the meantime I have made a connection from the router via Powerline (electricity) to the remote point and attached an AccessPoint there - has been running almost flawlessly for 2.5 years. I had to unplug and reconnect the powerlines twice, but otherwise.... performance is good, even if several devices share the connection.