methylone from wiki- 357 mg/mL (20 °C)
mdma from anecdotal - at least 200mg/ml v.quickly
On a chemistry front, methylone should be more soluble but I doubt it would be significant unless we're talking about mass production of the compounds.
What solvents are relevant to the procedures you're using? Really, you're going to find similar solubility for either the hcl salt or freebase for nearly all solvents. That hydroxyl substitution that confers polarity won't change much for that large a molecule.