Stillrunning This seems like a clever set-up to me!
I do something similar, but I use the owner's private space for installing apps that require the play store to be installed (I prefer Accrescent). Therefore I do not need shelter. I use Mixplorer to save the associated APKs and copy them with the Inter Profile Sharing app to the owner profile, which runs without play services. Then I turn them off in the private space, so they can still be updated. In the private space I run only apps that require play services. In practice I unlock it only a few times per week, because in my case there are only a handful of apps there, which I do not use frequently. Those moments are also good opportunities for updating the apps I installed through the play store.
The advantage of this setup is that I can mostly work in the owner profile, without play services, but with secure app installs. In the owner profile we have more privileges (e.g. battery, internet and system settings) and fewer issues (I encountered some bugs in user profiles). Also switching from owner to private space and vice versa is more convenient than from owner to another user space.