A:AnswerReplacing the motherboard with a different model can be tricky, depending on exactly what the new motherboard is. Probably your best bet would be to contact the Geek Squad, who should be able to steer you toward compatible replacements.
A:AnswerI think it would be a good choice. The power supply in the computer is 500 watts, which the calculator at https://www.newegg.com/tools/power-supply-calculator/ shows is more than required if you remove the 1060 that comes with the computer and install a 2070 in it's place.
A:AnswerBecause it's got a 500w power supply and you'd be replacing the existing 1060 Ti card, the power supply calculator shows that it would be able to handle an RTX 2070 without needing to upgrade the PSU.