Did you see that there is now waydroid support for sailfish?
there are two ways to install it, either a full virtual android environment, or one pr. app basis.
I just flashed sfos 4.4 and installed CHUM which as far as I can see is the newest solution for an app store.
I managed to install both solutions for waydroid, but havent gotten virtual android up and running.
if you are curious, check out nick's linux experiment youtube channel to see waydroid in action on a standard linux installlation