google wifi and aiport time capsule

Since Apple is no longer updating it´s magnificent Airport Time Capsule, I wonder if I could be able to still use it as my router and add Google WiFi mesh units. as of today, this is my setup:

- My adsl broadband provided by my Internet company, connected to my Time Capsule, that provides WiFi to my home. Since it´s a 3 store house, I use 2 airport express as range extender for my WiFi network (My Time Capsule is on the first floor, one aiport express for the other stores). Oddly, both of them show as connected and extending directly to my Time Capsule, not one extending my time capsule and the other extending the one that extends the time capsule, which leads to a very weak signal when connected to the farther airport express.

Since I wish to have a very Strong signal, I´m willing to try Google´s WiFi, the set with 3 pieces, but I wouldn´t like to lose the easiness of my Time Capsule´s back-ups. Would it work it I set up like this:

- My adsl broadband provided by my Internet company, connected to my Time Capsule (as a router), than a wired ethernet acble to the first Google Wifi as range extender and to create my mesh network.

Would it work?