I don't want to leave LO overnight yet

To me the dog would be the deciding factor. No way go along with it.

No, you sound very reasonable.
Let her take it however she chooses to, and continue to do what's right.

I'm surprised she would want to have a one year old who barely knows her for the night.
I'd run a mile at the thought!

You are not unreasonable.
The dog is probably very jealous and therefore potentially dangerous as he may lunge and bite. Best avoided.
If your MIL is always unhappy then you will never please her....nor do you need to.
Stick to your instincts and do what is right for you and your son.

Absolutely no way should your little one stay away from you overnight until both you and he are happy to do this.
In the circumstances with covid and an aggressive dog that is a definite no anyway.
My youngest daughters mother in law wanted DGS to stay with her from weeks old and got very cross that DD and son in law wouldn’t let him stay.He is two and still hasn’t stayed with them.
The first time our DGD was to stay with us,DD and son in law missed her so much they came to get her!She is four now and stays with us regularly,her choice.
It’s hard but don’t be manipulated.There will be plenty of time for sleepovers when he is older.Your baby,your rules?

You’re definitely not being unreasonable. What’s their plan for the dog when you’re LO is at their house moving forward? That would be my no 1 concern.
You know your son best, you’re his mum so know what he can cope with, so keep being a good mum and putting his comfort and safety first.

Lesim91 I don’t think you’re being unreasonable. An aggressive dog and a small child shouldn’t be under the same roof. Based on that alone it would be a non starter for me.

Mine didn't stay overnight a another person's house until they were about six.

They didn't want to and it wasn't necessary.

Do what you and your child wants. Nobody else counts in this equation.

I think you are perfectly reasonable with this. It is not reasonable for them to expect to have your little one stay at the moment. Young children sometimes become unfamiliar with people they may know well but have not seen for a short while. I saw my eldest grandson on an almost daily basis from when he was a baby and he was very used to me and stayed in my house from about a year old.
When he was about 20 months I went to OZ for five weeks. When I returned home he was unsure of me. I made no attempt to invade his space and as other family members were there we chatted and riffled through my suitcase -initially he would not accept a gift I had brought back - then suddenly he got down from the sofa and came and hugged me! - things were back to normal.

No not unreasonable and you have proven it is not an issue with trusting her by agreeing to a day trip. She should be happy to have this opportunity, why would it be more important that he spend time there asleep? Babysitting is usually looking after little people who are mostly asleep while their parents have dates. An afternoon is quality time.

My advice is to agree your boundiaries now with your husband and stick to them so you are both always on the same page.

No way. Not with that dog.

Tell her to take a hike! Honestly, I am sorry to be so blunt, but why, just why, should you entrust your child to the care of someone who has a dog that needs muzzling and who barely knows the child?

Just say NO !!!!

If you have need of overnight care for your child, then that is a whole different ball-game because there is a sound reason for you to be looking at who might be most suitable - but your MIL has no right to ask this of you.

You say you do not want to leave your child overnight YET - there is no reason why you should want to leave him at all!

The dog is enough to make you say no. If she takes umbridge then that's her problem.

She has no right to put this pressure on you, you are the mother follow your instincts and don't question them, you need to feel comfortable about any such arrangement. An aggressive dog would always be a worry, it's heart breaking to hear about young children and babies mauled by a dog sometimes fatally. On occasions these tragedies have occurred at a family member's home, it's too late to be sorry once it's happened.

I do like dogs and many are great around children, but I think a child/baby's safety has to be paramount around one that is unpredictable.

No you are not unreasonable. We have just had DGS1 and DGD to stay overnight for the first time and they are 6 and 3 and were ok but know us well as we mind them twice a week and had each other.
My DS had to be brought home age 10 when staying with a friend (we brought the friend too) and wouldn't stay away after till he was in his teens.

My in laws had the children overnight occasionally so that in a crisis they would be happy away from us. No. 2 caused a lot of problems in utero and in the end dear MiL had No. 1 for six weeks - an age for an eighteen month old, who was totally untroubled and adored her grandparents. We were glad we had prepared our child for this, but there was no dog (would have been a definite no no) and MiL was totally committed to doing things our way. We were lucky.

Have had one GD a lot as a small child, the other two much less, and we know them less well. Being a grandparent is a privilege, not a right, do stick to your guns.

Seems extraordinary to me that some grandparents seem to feel they have a right to their grandchildren. The child is not theirs! Stick to your guns!

No way and the dog should be safely secured away in the future when you do visit.

Your baby, your rules. I have had my grandson overnight in the past when he was about 8 months old. That was instigated by his mum. I have never pushed for an overnight as he's not my baby and I look after him two days a week. Your Mil is out of order.

This a child , not a toy or a pet! She is totally off

You are being very generous on offering a compromise - yet, she doesn't appreciate your gesture
You know you dont have to negotiate this, right? You don't have to offer day visits instead of overnights.
This is not a coparenting and custody agreement situation.

I would be reticent to over day visits - the dog is a huge red flag.
If dog is going to be present, no visits with mil, for your baby's safety. Hill to die on. Your mil is picking her selfish whims over her family.

Has mil tried to train her dog? Address this aggressiveness?
The dog is a victim in this case.
You are under reacting.
If you haven't tried yet, your dh should talk to her about the boundaries you and your dh want to implement and consequence for breaking them.
Example: you visit, dog is there, you leave right away

Bottom line - you said your mil was always unreasonably demanding and never happy.
Nothing you can do will change that.

Do what's best for your core family and mil will have to deal with her unreasonable expectations.

By now you must be feeling validated, so I hope you will stand up to your MiL and keep your baby safe from both the dog and any exposure to Covid19.

If you don't want to leave your young child with your MIL, then don't. It is entirely your decision and she is being unreasonable by "taking it personally". In fact I'd call taking it personally a deliberate way of trying to make you feel bad. Don't let it.

No, you certainly aren't being unreasonable. You in-laws didn't see your little one for months, they don't know his likes and dislikes, and they've got an aggressive dog - besides which, your son is still a baby and too young (in my opinion) to be away from you overnight.

Let her think and say what she likes - at least you've got the backing of your husband.