dynamic dropdown based on two matches

Use this:

=OFFSET($H$2,MATCH(1,($F$3:$F$15=A3)/($G$3:$G$15=$B$3),0),,COUNTIFS($F$3:$F$15,A3,$G$3:$G$15,B3))

If the data is shuffled, this formula might fail though.
E.g. all the values that OFFSET combines need to be a contiguous range in the original data set.