@mautz

SUCCESS! What would we do without you!

Indeed you need to create the file you mentioned and activate the sensors (see here)

So I have a fully working current SailfishOS version on the Nexus5! Mille grazie!!!

There is one thing I don't really like: You seem to have tuned the default max volume settings in the CM13 port. For me these settings are too loud. I have some clipping in my speaker. Would it be possible to tell me where I can modify these settings? THX in advance...

As silly as it sounds I would take into consideration to work on a fully up-to-date CM12 port again. Why that? Well the guys of ubports still work on a cm12 base for Ubuntu Touch on the Nexus 5, and the main developers all own one. We could align with them and their work. They are working on an patched kernel for anbox, for example.
Also we would have video recording back! The ubports team is working on bug fixes for the camera. We could probably benefit from their work.
Also in the future we could have a common Halium base for the android part of the two Operating Systems. Wouldn't that be cool?

I am in loose contact with them, as I have a Ubuntu Touch (OTA5) image running for testing. It's a small but relly cool developer team. And they made huge progress.