You almost definitely would benefit from getting a stencil. Instead of a hot plate you could do a toaster oven. I got an "air frier" convection toaster oven at walmart for $50 open box. It's perfect for reflow. Also take one that you've already ruined and test the melt temp on the plastic them put a thermocouple probe on the plastic.

Is there any particular reason you can't use the featherwing package that adafruit sells? I've seen a few other folks on tindie selling other board and screen combos but personally, for my money, the feather format is pretty good for almost anything I could want to do in this form factor.