Is it permissible to wash some Wudu organs twice and others three times in a single Wudu, or is it obligatory to equalize the number of washes for each organ?

It is permissible for someone performing ablution to wash some of their limbs twice and others thrice, and uniformity in the number of washes is not a condition for the validity of ablution. Muslims have unanimously agreed that washing the limbs once is obligatory, while washing them thrice is Sunnah. Thrice is the complete way, but once suffices.