Quote:

I believe in both cases (Dsus2 and Dsus4), the 3rd is always dropped (not the 5th).






Correct.

A "suspended" chord (I hate that term by the way) is neither major or minor because it has no third.

The '2' or the '4' replaces the third.

To the O/P:

The greatest musician I've ever met (pictured at left) gave me the best musical advice I ever got: Learn harmony and chord theory..