ATMEGA32u4 for keyboard

[ddolzhen]

So I'm trying to make a USB keyboard on a self-designed PCB with ATMEGA32u4 (or the Teensy 2.0 board, but I don't know how to merge that with my PCB) and there are 2 things I'd like to clarify:
1) Can I load a Teensy bootloader onto a factory new ATMEGA32u4 and use it with Teensyduino?
2) How good is Keyboard.print() method for designing a full keyboard with acceptable (compared to a good USB keyboard) latency? Or the 'micro manager way' (both explained here https://www.pjrc.com/teensy/td_keyboard.html) ? The other option I was considering is using LUFA libraries for HID devices, but that looks like a lot of pain

 

[ddolzhen]

I was also wondering if I could use Neopixel libraries for LED together with Keyboard.key("...."). I would assume they are both using interrupts.

 

[GremlinWrangler]

The only way to get a teensy bootloader is to buy it from PJRC on a board, though if you use ISP you can probably use the teensy libraries without too much hassle.
Print is probably not the way to go if there is any need for this keyboard to support holding a key down, though press and release will probably do what you are after rather than manually allocating the slots, though if you are trying for minimal possible latency for a fighting game or something that might make a difference.

Have not personally tried neopixel+keyboards but would expect trouble since neopixel really does not play well with others, if it is a short strand you may be able to get away with blocking interrupts while it feeds the strand.

It may be worth a look at the Ergodox and related keyboard projects.