A:AnswerNo, WIRED carplay isn't compatible with MagSafe. You'll need to plug your iPhone into your stereo directly for carplay, which means you don't need the MagSafe charger. But you can still use it as a mount only.
A:AnswerYes it is! I have the 14 Pro and my fiancé has the 14 pro max. I was concerned that his would be heavier and not stay secure on the magnetic holder but we have had no issues and seen no difference between each used.
A:AnswerI have the iPhone 12 pro max and it does fit, but if you have a case on it needs to be a magna-safe case to hold it securely. A regular case won’t give it enough grip. Just make sure the bottom “foot” support under the clip sits securely at the bottom of the vent as well and you shouldn’t have any problems.
A:AnswerNope. Not unless you have a newer high end car that supports wireless CarPlay. I don't use that USB port on my stereo personally. I use a usb plug into the cigarette lighter.