restarants require men to wear long pants for dinner (not buffet) except when they choose not to enforce it from place to place and day to day. I have seen jeans acceptable but not always!!! Best to bring a pair or two of something decent. I’m not a fashion queen nor the police so I will not comment on style.
It never used to be a problem wearing short sleeved collared shirts but then neither were dress shorts for the guys. As far as I'm concerned a collared shirt can be a polo, button down, button ups and both can be long or short sleaves, its Mexico it's hot, it's humid there will be no long sleeve shirts being packed in our luggage. If that dosen't work I'll cut the toes off a pair of sox and wear them as sleaves. T
short sleeves were fine when we were there in march brought some polo's for hubs and they were fine .. I only brought him a couple pair of slacks he would pop those on go to dinner run upstairs and get back in shorts and hang the pants back up for a different day