Disclaimer: I'm not an EE and don't have a thorough understanding of transistors. I also struggle with selecting transistors. With that said, I tend to default to the garden variety 2N7002 signal mosfet (2N7000 if you want through-hole) for this type of application (low side switch). Gate...
Not really. I still don't have a (semi-universal, not involving adhesive) method for attaching the battery outside the case. It could be a free-hanging box I guess, but that's awkward. I'm open to ideas.
Been enjoying hearing about this in IRC. Tashtari is a PIC assembly wizard.
My default UART speed has been 2Mbps for at least a decade... even the most pitiful micros can do this. Get with the program, rpi! :ROFLMAO: