Yes. The red LEDs will have the lowest forward voltage of all the colours, probably 1.8V. The 220R resistor will drop the remaining 5.0-1.8=3.2V. So the current through it will be 3.2/220=14.5mA. The Arduino pin will need to source twice that, so 29mA. The absolute max current for an Uno/Mega pin is 40mA, but you should keep below 25~30mA for long life, so 29mA is just about OK.
No idea as you have given no details about the motion detectors or how you are powering the whole circuit.
Ok, thanks. There are several ways to power an Arduino, other than usb.
The data sheet says the sensors can use up to 60mA each, so 240mA. The LEDs could be 4 (or 8?) on at once (UK traffic lights have a different sequence to US, red and amber on at same time), so that's 4x30=120mA or 8x30=240mA. Total 360mA (US) or 480mA (UK), plus 50mA for the Arduino itself, so 410mA or 530mA. Limit for usb is 500mA.
However, 40mA is typical for the sensors, 60mA is the maximum. The amber and green LEDs may use a little less current than the red, because of their higher forward voltage. And the Arduino may be more like 30~40mA. So I suspect you won't go over 500mA, but it could be close.