Will this set up improve my current Wi-Fi signal?

Hi all,

I'm looking for a way to improve my Wi-Fi signal, however I don't want to get rid of my current router to do this. Let me explain my set up:

I currently have a Netgear X10 R9000 Router, which I am more than happy with. Its fast, reliable and even its Wi-Fi works well. I also have a Netgear EX7300 Extender, which sits in the farthest corner of our house. Once again this gives a good Wi-Fi signal, however on a different Wi-Fi SSID. I have Fibre Broadband and get around 76mbps speed, which is good especially when I have 5 children all using the Wi-Fi signal! The house we have was built in the 1950's and so is very solid. Theres no plaserboard walls, they are all brick and stone (including the interior walls) - So as you can imagine this doesn't help with Wi-Fi Signals.

On a busy weekend, we can have anything up to 14 devices all using the internet, including iPads, iPhones, Amazon TV, Sky TV, PC's, Macbooks and so on - a very busy place! So I'm looking for something that I can use, with my X10 router, in order to speed up the Wi-Fi and also make it better accesible in our solid built house.

I've seen these 'mesh' systems and takena a look at the reviews, and from what I can tell they are the way to go, especially as they can use one SSID and decide themselves whether to add a device to the 2.4ghz or 5ghz signal. But I have a few questions I wondered if I may ask the community:

1. Can I use my X10 router instead of one of the Orbi nodes as the main router? I saw that I can with other mesh systems by making them bridged, is this something I can set with the Orbi?
2. (Heres a difficult one to answer) Will it improve my Wi-Fi speed? i.e. I guess i'm asking whether it will be faster than my current X10 Wi-Fi speed?

I hope i've explained everything correctly, and thansk fro reading this, I hope someone out there has either done what i'm looking to do, or knows about it - that would help a lot.

Thanks in advance