Unknown error 12746, no audio, bad bluetoothUnknown error 12746, No audio output out of jack, bluetooth does not connect sometimes. Not sure if these are related....
Answer to "Low or no service after screen repair"These are difficult phones to work on so I can see how this could happen. Sony phones require a special sealing procedure to prevent the screen and back cover from separating. I would recommend looking for a shop that specializes in Sony repairs or bring it back to the shop you had it repaired at. You may still have warranty through them. Ifixit has a large list of reputable shops also. As far as the cellular connectivity issue goes, there are many small contacts and antennas inside the xperia's that can be interrupted . I would recommend having a professional check all these connections and replace the main antenna board while he/she has the phone opened up.
Answer to "Adhesive will not stick"This seems to be a big issue with S5's and Sony Experia's. Best thing to do is to make sure you thoroughly clean frame, apply a plastic adhesive activator and use high quality adhesive's. Also you need to check your frame/chassis for damage, separation, and or whether or not its bent. We've been looking for a supplier for Sony Experia OEM water proof adhesive. If anyone knows where to get it can you please let us know. Thanks