OP here-
It is store bought meats and cheeses, assemble yourself sandwiches. Mom buys fancy chips and pickles.
For the BBQ, someone drives 45 mins. to the BBQ place.
UPDATE-
I just spoke to Aunt T. and her DH, my brother. He has not even heard from mom, and he was happily surprised about Christmas Eve service.
As for the cookies, I asked, "with your two little ones, it may be too much to both the trains and the cookies. What do you think?"
"Why not?? We have been doing the cookies for at least 35 years so we should still do that one. And there is enough room for both, like we have done before."
I replied, "Sounds good to me! Let's coordinate what candies we are bringing to decorate the trains." (off-topic discussion of gummy bears getting run over by the engine car)
"Oh, DB, does our sis-in-law (Aunt L.) have any special traditions that we have been missing?"
"Not that I know of. They have been married longer than me, and have a child a few years older than my oldest, plus her parents live 5 mins away from ours so if she does have a tradition, she does it there."
Chatted about travel plans back to their town and general chit chat, and the good-bye.
So, Aunt T. has no concerns about doing both the trains and the cookies.
I might call the other DB, (Aunt L's DH, my baby brother) but I cannot see any problems there, either.
Mom has never been one for fun. (edited out two boring paragraphs of how dull she is, and really seems to have no friends. I could not name ONE friend of hers.)
My kids like the cookies. With the leftover dough after we have made the Santas, we make traditional Christmas cookie shapes like trees and bells and stars, but then we also make red trees and green stars and then on to maybe a martian or a snake done freehand. We have years of pictures. One year we made an entire army of minions. They almost burnt because they were small, but we still ate them!
So, the cookies are on. I will bring every last bit of supplies from my home, and I guess when I see mom, I will have some configuration of the kids ask Grandma when we can make cookies and decorate trains, like always. And if she pitches a fit, well, I just do not know. My in-laws live in my town here, and I do not know sis-in-laws (Aunt L) parents to borrow their kitchen. I have not lived there since age 17, and I am not on FaceBook to see if anyone is still around.
I can see mom's fussing over the time with the church service, but we could do it the day before. Or the morn of Christmas Eve. We can, and have, worked around nap times and travel plans. We jsut need to work around Grandma now, it seems.
So, come December 24, Santa WILL be getting his likeness made into cookies, as usual, somehow! And the candy train will be on display for him to see, also.

Merry Christmas e-hellions!