The only problem with those substitute chords for Dm7sus is that they include the third, F, which the sus4 is supposed to replace with G.

Since a sus4 chord substitutes a fourth for the third (as opposed to a sus2, which subs a second for the third), there's no difference between a dominant7sus4 and a minor7sus4.

So Dm7sus is the same as D7sus. The difference is in the scales they represent, assuming that one plays the third in the melody.

There is no satisfactory solution to this in iReal Pro. One can put an approximate chord in place and use text to write in the correct chord and raise it above the line.

Obviously, the important feature request here is the ability to construct chords from one's own notation.

Cheers,
Jer