Quad SPI series resistors on lines for short circuit protection?
3.6V Family Logic were typically 22 +/-50% typ Ohm driver impedance so 33R series parts are used for 50 Ohm bus, given tolerances on source.
The FT813 datasheet indicates on p49 of 63, for VccIO=3.3, Rsw = 6 Ω typ, 10 Ω max, thus twice this for differential.
220R is not needed for short cct protection.  Rather you choose according to cable type.  Std. twisted pair is often 110 or 220 depending on insulation thickness and twists/ft or /m. On PCB Zo depends on track gap/width ratio to gnd plane or trk//trk, so if you don't know assume it is 100 Ohms. (get Saturn PCB ...exe free, don't guess)
12MHz is pretty low clock rate for 12 cm unless your 12 cm is a big ugly jumper wire pair. ( consider 10x BW for margin)