Oh gosh..I completely understand where you are coming from. We have had pets the whole of our lives. I have a range of experiences to share..that may or may not be of help.
I have had family come to us who have hated the cats, mentioning cat hair, grumbling about allergies and even saying that they find cat hair everywhere for weeks when they've visited. I found it really embarrassing and being much younger I was too ashamed to bounce back a "hey, you dont HAVE to come visit! Next time lets meet at a cafe" type response.
One came to stay and of course I kept their bedroom door closed, I even borrowed next doors hoover who was pet free...and hoovered their room..but it eas inevitable that cat dander, fluff was in the air etx. For thr whole weekend every hour or so there would be a comment about itchy eyes,
A sore throat, "how can u cope with this" etx etc i felt terrible, but it wasnt my fault that they had cat allergy. Personally in their shoes, knowing this I woudlnt have asked to stay.
another older member of the family who lived in a show home... used to comment about fidnibg fur on her clothing etc..I had short haired cats, leather furniture and wooden chairs so im not sure what the masses of cat fur Was sticking to , to transger to her, but yes i guess fur does! I Simply accepted what they were saying and i do accept that everyone has differnt lifestyles and different experiences, likes and dislikes.
Personally if I go to someone else's home I politely adhere to THEIR boundaries as the space is THEIRS ie taking shoes off, only eating at rhe table, kids not allowed cake on the sofa etc etc.
I think people forget that circumstances change for one set of families while it wont change to match with another family ie ill quietly never forget not being permitted to a family wedding because the venue was not suitable for children.
At the time I had two under 4...and had never left them at night, not only because one was prone to severe illness but also the guests would all be family so away too!! (not that they baby sat anyway) vut also the wedding was a 3 hour drive away so would have meant driving to the venue whixh was v v rural, leaving the kids in a hotel room with my partner ..who would not accept having the kids over night without me (another story)and then spending a few hours at the venue, getting a taxi back to hotel, all the disruption to kids routines plus expense..without them being allowed to join in.
What did I do?
I politely and with all my grace, sent an apology RSVP stating we wouldn't be there and we sent them a voucher and a "have a wonderful time!!"
Can't wait to see pictures type card.
Not once did I try to bargain with them about bringing the kids!! Because they've put down their boundary and I have the manners to accept this.
Sweetly within 5 years they also have two toddlers and would never imagine leavibg them out of anything!!! Because things change along with experience and exposure to new situations. They'd never have left family members out had they realised the impact but there are no bad feelings because at the time, they didnt want the kdis there.
Another situ (actually pet related) was similar to yours in that a family member also had a rather unruly dog,it happened to be quite a strong dog, a bit smelly and jumped up (although they didnt seem to notice the smell as I guess got used to it)
They woukd leave the dog while at work, queitly in a crate having taken it for a walk and a run first thing and then when they got back 5 hours later. The litrle dog appeared really ok with this..anyway weekends they didn't have this routine and doggie had free reign. Im not commenting about this, I have no opinion other than I agree with any animal having as muxh freedom as possible.
Anyway, whenever they came over, we would have to lock away our many cats as this dog was a breed that chased and shook cats. (Again no judgement...lots of dogs have been bred for specific tasks and then cant be expected to pack away their instincts beacsue we decide we dont agree with them!!)
Anyway the dog had very wiry hair whixh would srixk into everythign, incidentla but a bit annoying...the worst was that it used to growl at the kids, and being kdis they would have food on hands when eating,and the dog used to come up abd lick them. It made me feel uncomfortable as I ddiht trust the growling and I dodnt think its fair for a dog that's not used to chidkren to keep being told off but exploring things but I also felt concerned for the small kids because they were unpredictable, the same size as the dogs face/ smar height so a small nip could be quite catastrophic.....the kdis weren't used to dogs so would try and touch it or kiss ots face, liek they did the cats...but the dog didnt like it.
The whole time they were in my hisue I was on edge and spent the whole time watching the dog..and my kdis.
Doggie had strong thick claws and would jump on the sofa, crawl into my lap and the kdis. If yorie a dog owner you might fidn this really sweet but I found it unbearable. Doggie is heavy, the claws hurt, I dont want dog slobber in my hair or on my hands and and and....
Sometimes they would 'crate the doggie making a massive deal about the poor thing being CRATED as though it was being isolated or tortured. I guess its not ideal but with elderly parents doggie was a trip hazard, it was trained, but once food came out or the kids made contact...it was too much for the dog and I can honestly say, although im no dog psychologist...that it was probably quite stressful for the dog..whixh then worried me even more because I dont want any animal to be stressed because of my actions and also, the natural reaction and emotions of thr poor dog may br to snap or get agitated...and with those jaws, once he locks on..he wont be releasing whatever he has without a fight.
A few years later they had a child of their own..I think then soemthing clicked..and now doggie is happily walked more, taken to classes, crated more or given space in another room and they dont allow dog to jump up etc. I think they realised that afyer their toddler was toppled over a few times that the behaviour wasnt "cute" or the doggie "just trying to be near us"
I once , when a student, had a pet mouse that used to sit on my shoulder and for some reason I thought it was appropriate, safe etx etx to take this little pet to the supermarket hiding in my scarf. It would pop its little head out of the little pouch I put her in to keep her secure and also keep her wee away from my nexk (I know, gross) but she was my little mate. Anyone who didnt like her, I kept her away from. Simple really....
Sorry,im rambling, but what im saying is that YOU also have the right to lay down polite boundaries.
Dont wait for their circumstances to change and govern the outcome.
You've got every right to politely say that it's not a good environment for A dog on Christmas day.
They might strop about it, and make silly comments, which youre not going to rise to xx and youll continue to have a great day without them, if this is what THEY choose to do. Also dont allow them to pull u into any sort of conversation about their alternative plans, if they find one. Just say "aah im so glad you've got a lovely day planned" etx.
Good luck x