We did Ohana for breakfast last March. Our DS was 15 months at the time and he thoroughly enjoyed it as did we! Stitch has since replaced Chip n Dale I believe but Mickey is still there and Goofy too I believe. Goofy made a great hat for my DS out of his napkin (great pictures) and Chip or Dale (not sure which one) spent forever with my DS just tickling him and cutting up! (We booked a late breakfast--10:05 I believe.) The crowd was pretty cleared out. Though we didn't get to do the conga line or coconut races by that time. I wouldn't have any problem recommending Ohana for any age.
That's my DS with Chip or Dale at Ohana in my signature.