I've been a FIFO wife for about 9 years now. I hope I can help you with our experience.
- tips on keeping the connection?
With all the modern methods of communication ar your fingertips, it's easier than ever to keep that emotional connection strong. We make sure to talk to each other every night. He speaks to each child individually, even if it's just a quick 3 minute chat. We also make sure to keep him in the loop on what's happening here. All the little things as well as the big ones. We like to send him pictures from our days, and sometimes videos. I also LOVE sending him a care package of goodies when he's away. Things he has when he's home that he can't get there, maybe some fresh socks that smell like our laundry detergent. Little things to remind him of home.

-Christmas away?
Christmas, and every major holiday, are very fluid in our house. We change the day to celebrate, to suit our schedule. We still enjoy the actually official date, but in little ways. My kids this year were stoked he was away for fathers day. I told them that we'll be able to get the marked down fathers day stuff the next day, so we can really go all put when he comes home. Haha, the poor guy walked in the next Thursday and was immediately bombarded with a tonne of stuff.

Is there anything else I can help you with?

My partner was FIFO for 2 years. 3 on 3 off. He was not in the country though which made it alot harder for Skype etc. Our kids really started to struggle as where he was situated the internet was terrible (Manus island, PNG) so Skype calls were very far between. We both decided the money wasn't worth it. So he is back home now and we're all alot happier :)

You can't have it all. Is the money really worth it?

I change the dates of Christmas and Easter to suit our schedule, birthday's get celebrated twice if necessary lots of face time calls.
The bits we struggled with is I felt resentful because I don't get a break, and he felt resentful being given a list of jobs to do when he got home. I have a cleaner once a week, a gardener once a month and a day with the youngest in child care once a week so I get some time to myself.

My partner is 2 on 2 off . We text and call, send pictures , we are use to it now , when he is away the kids and I do movie night And hang out. for us tho the kids have more of a bond with me than their father .

Im not a FIFO wife however it must be hard. When my partner goes away for trips for work we call each other every night. Maybe you can skype with the kids. Set up a time for the kids to call maybe before tea or after. Then once they are asleep have an adult skype.