i would say rithm its an absolut basic, because once you know the scale your playing in, you can actually play "wrong" notes if you hit them in the right time (off time actually) and because funk its, as james brown said, just like playing all instruments like they were drums...
so work on polirithms,mixing up 3/4 and 4/4 and stuff like that... and try some 6/8, 3/8, 12/8, 6/4... ng the drums and so on, and once you´ve got all the complex rithms and you´ve learn how to "elude" strict scales and you can impress your people with amazing chops remember that GROOVE must be your moto, your only objetive, no mather what do you do to get to it. i think some old school funk will help with theese, so try motown, stax, check out dyke and the blazers, james brown and then some sly and the family stone, funkadelik, parliament of funk... but i woudnt get too much into slap funk untill you can play it really nice figerstyle because it might sound impresive and somehow stop your progres... well that happend to me, might not happen to you...
ow! and dont listen only to the bass part when listening to funk, keep your ears on the kick drum and the charles... well just dont miss a beat...
hope this helps