Happy Holiday Season, and happy shopping! The "in time for Christmas" question... I can't be certain for you, although if you are in BC or Alberta you chances are good until about the 15th. For everyone else, if you want it for Christmas please choose a tracked shipping option.
Water erasable extra fine tip blue pen. Do not iron before you have washed the markings away completely or they may become fixed. Test it on your fabric first just to be on the safe side, but I have used it on cotton and cotton linen and it worked fine.