I am unfamiliar with the smart phone brake controller. Seems a bit overboard, but I am a dinosaur.
I'd be more inclined to go with a tried & true brake controller like this:
https://www.etrailer.com/Brake-Contr...xoCLbEQAvD_BwE
As for your choice of WDH, you may find it easier to find one that includes sway control with out the friction controller in your Eaz- Lift you are considering.
The size of your trailer would be excellent with the Andersen WDH, in my opinion!
https://andersenhitches.com/pages/we...ribution-hitch
Murff