[Edit: Corrected availability date, initially stated as spring 2018, should be spring 2019.]
For what it is worth, I have found two phone alternatives, that do not yet exist:
Purism are now trying to crowdfund a privacy respecting phone, the Librem 5 phone. Will run their Linux variant and include Matrix for communications. The idea is that it will work both as a normal mobile phone and as an ip-connected computer (using wifi or a dataplan SIM card). The crowdfunding campaign has another 39 days left and ETA for the phone is spring 2019. (There is a developer kit with ETA June 2018)
Also, Jolla have announced that Sailfish OS will be available for the Sony Xperia X in October 2017. The project is based on Sony’s open device program and initially targets one specific model. Unfortunately, the procedure is rather involved: You have to buy a stock phone separately and reflash if with Sailfish OS.