The current through the 100 ohm resistor is about 50 mA in "transmitt" state, and about 10 mA in "receive" state, so the max. power loss in resistor is 250 mW, but it is the max. instantaneous power loss, the average power loss is less than 100*((0,05+0,01)/2)^2 = 90 mW, that is nothing that wouldn't make 1206 resistor.
There is already the 100 nF capacitor in parallel with the big 470 uF one (see fig.). Because of the speed of the CAN of 125 kHz, 100 nF is not enough to "average" the supply current of the CAN transceiver.
The lengths of the wire is about 5 to 10 meters from the power supply to the receiver/transmitter and than about 1,5 m between receiver and transmitter.
The main problem is, that the receiver is sensitive to the changes of the amplitude of transmitted signal, so when there is something, that changes the power supply voltage, it affects the transmitter's signal, because the transmitter power amplifier shares the same supply. So the CAN current "modulates" the amplitude of the transmitter signal and so interferes in the receiver.