Cloth would be fine for a healing monk, leather would be better but use what you can. I leveled my Death Knight to 80 (tanking in RDF) wearing cloth heirloom chest and shoulders just for the +XP.
You get some smart/silly comments about why you're wearing cloth. But at the time I only had enough JP to buy 2 heirlooms for the rest of my characters so cloth it was!
Doesn't really make a big difference. The cloth armor often had better stamina than the out of date green plate the dps Warrior was wearing but rofl omg it's cloth l2play noob tank.
Yea it would be noob tank, stamina is not the be all and end all of stats