Concerning thickness and haptic, mass data would only be fully informative if the paper would be of exactly the same quality. So, one should be careful compairing different mass data.
If one subtracts the foil mass than the Adox paper would have a base mass below that one you gave for the Ilford paper. And on assumption of identical paper quality the Adox paper should indeed be thinner.
What I want to say is that one easily compares apple to oranges and that figures from data-sheets not neccessarily are true and if, than only to be evaluated in the right context.
Sure, and Agfa once gave two data - thickness and weight. Maybe Mirko can tell us more.