So after checking their website and Facebook page, calling ALL the WalMart's in Costa Rica and most of the time being disconnected (sometimes as soon as the # is dialed) NONE of which had ANY information on them, I finally got a response back from their Facebook person - at least for PART of my question - at least for the Christmas week.
CHRISTMAS EVE - Tuesday - December 24 - Open till 9pm
CHRISTMAS DAY - Wednesday - December 25 - 9am-8pm
(Last year they were open their normal hours December 26 to December 30 - 8am-10pm)
NEW YEARS EVE - Tuesday - December 31 - ???
NEW YEARS DAY - Wednesday - January 1 - ???
(in 2012 they were open:
New Year's Eve - Monday - December 31 - 8am-8pm
New Years Day - Tuesday - January 1, 2013 -9am-8pm
from my LivingLifeInCostaRica.blogspot.com/2012/12/open-closed-christmas-holiday.html)