Help with MIL

Perhaps if you casually mention that you'd love him to have expensive shoes like the ones she bought but can't afford them, she'll send the money for them every few months? Accept graciously - my DS grew out of a pair of good leather shoes in 2 months! I wish my MIL had offered to buy some occasionally!

Accept the best of the best and never feel judged.
She probably has been longing to be an indulgent granny (and she doesn't live next door).

I feel as though she acts as my child's mother, And I barely get a chance to see him because they hover over him and do everything. They do not help clean after themselves and have only made one meal since being here for 6 days now, so I am not sure how helpful they are trying to be.

I know 10 days is not a long time but I'm stuck with them 24/7 for those 10 days, much of which without my husband because he's at work.

It's more of the fact that they make us feel judged as not doing good enough for our child because we don't buy him 150$ shoes that he will outgrow in a few months.

They are very well off people, and my MIL has never really had to work her whole life because of this...so a better word is more entitled and they buy the best of the best.

Sorry - misread - only 10 days, I should have corrected that

They are only there for a month and realise you have a lot on your plate with a one year old and a new baby so are probably trying to be helpful.

Wipes are so bad for the environment as they contain plastic (single use) and personally I wouldn't put a one year old in plastic shoes or trainers if you (or they) can afford better leather shoes.

Personally I do have durable plastic toys for when the DGC come here as well as wooden ones - are they very ecologically aware? Organic cotton clothes could come in for both children, better than acrylic.

I hope you can cope with their visit, it's only 10 days - perhaps let them play with your toddler and concentrate on your baby for that time. They'll be gone back overseas before you know it.
Perhaps you could discuss this with your DH when they've gone home and explain that you found them rather overwhelming and you need his support.

Grit your teeth and wait until they've gone. Then have another birthday celebration with a cake you've made (maybe inviting other toddlers/family/friends who didn't get to the first celebration).
As for the clothes, shoes and toys, well... obviously you have to use some of them at least as it might be noticed if you didn't. But you could decide which to keep and use (let some of them show up in family photographs?) and quietly 'lose' the others in the back of a cupboard, and maybe send them to a charity shop after a year or two. You can always say they broke/wore out/were outgrown.

It is hard to give up the mother role, so allow MiL a little leeway. However, maybe between now and the next visit you will get some other - good - advice from other GNs to help you deal with her. You certainly are not being unreasonable but perhaps a little subtlety is required.

You’re husband needs to tell his Parents to back off and stop undermining you. As you rightly say it’s your child and what you both say goes. She isn’t being at all sensitive to your feelings and is risking alienating herself.