Serebii mentions doing things in Lumiose to gain Style, but doesn't mention if you can keep doing the same things like hotel work and riding goats to grind out more. Does it cap when you do everything once, or what? --- The heart is shaken more by a single action than a thousand words.
Seems very possible to grind it. I haven't done all the restaurant meal battles and a few other things and I'm certain I'm maxed out (or very close to it). I have the Mr. Bonding O-Power you get at high style etc.
I don't know really. I tried going on a loop with the cab and Lumiose Press to grind the style but the price of Mega Stone did not lower. Then I ate at Le Yeah for the first time and it did lower. But I don't know.