There are actually no Christian Saudis at all.
Although Xmas is not celebrated publicly nor it is part of our culture/an approved holiday, private communities with Christians are allowed to celebrate it normally. I personally do see people congratulate each other for it where I work. Many Christian expatriates here. I once joined one Halloween event with a friend when I was little.
Ramadan and Hajj have enough off days to gather around, sleep happily, stc. Plus there is the national day, week ends and the annual one month vacation for me. So really, no complaints about lack of vacations. But I do want more ha ha