1. Pro micro and clones are incompatible with Teensya 2.0 There are two problems: pinout (different pin names, not big deal) and bootloader (arduino bootloader suck). Rest (uC, crystal, USB section) are almost identical.
I tried to program old
WaxBee into pro micro. With success. But I need external programmer to do that. More info here: http://forum.bongofish.co.uk/index.php?topic=2556.0
Newer WaxBee version have smaller size thus You can use arduino bootloader that are inside pro micro. Just programming process are different. WaxBee can program teensy or generate hex file. You need manually call AvrDude with specific parameters. That's probably the most important difference.
2. You need working EMR pen. Original Wacom pen will be excellent as long as it working (moisture and time may destroy everything). Replacement pen may working too but I never played with that.