Welcome, glad you're here!
1) No, it shouldn't squeak. It's unlikely to be a mechanical problem now or later, but the noise may become objectionable. It work for me.
2) Yes, that's normal. There's no power lift or even strong hydraulic lift. As long the pneumatic tubes are holding it open without sagging, there's no problem.
3) Electronic keys are expensive, and even if you purchased one online it would still have to be programmed by the dealer to work with the car. So overall that price isn't out of line compared to other auto makers.
4) I'm assuming you have the hybrid and not the plug-in version. To my understanding a spare tire will fit in there. Others with your model can confirm that.
5) No experience at all with them, so can't offer an opinion there.
Android Auto is available for the 2019 models, but I can't say for sure if it was there for 2018. Again, someone with that model year will have to answer that question. I did find a Kelly Blue Book review for the 2018 models and it says AA is available, but it didn't say if it was part of the Tech package. But it did say it should be there on an LX model. Note that for AA or Apple Car Play, you have to connect the phone to the car via USB. AA and Car Play don't work over Bluetooth, although the car does support the usual Bluetooth functions (phone calling, address book sync, text message reading).