My original thoughts were: DH can be as appalled as he likes - as long as he keeps it to himself. I know he is working away and not away having fun, but none the less - you are the one who is there day to day and what you say goes. If he carries on about it, tell him to take some leave, come home for more than 48 hrs and sort it to his satisfaction.
However, if I had to work away and only came home at the weekends I wouldn't feel I had to 'put up and shut up' with whatever was happening, but I would discuss it with the parent who was there all of the time and see what could be done and how I could help with that. I wouldn't be 'appalled'.
I do allow a toy (or two) at the table when they're very little, but they 'sit & watch' they're not played with. It seems to work.
Before MN I would have said 'Oh FGS just make her sit there & don't allow her to get up and down' and in my world, that's still what would happen. However, I accept that perhaphs I have just been lucky with all the children I have ever encountered because they've all done pretty much as they were told (sometimes needing telling quite firmly & consistently!!), but since being on MN it's harder to know if there are children who just will not do as they're told or if others perhaphs aren't as 'firm' and unwavering in their methods
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Does it bother you if she brings toys to the table?
As for the older children, just tell them that when they were small like her they were allowed to as well, but once they were big enough to understand that it's not good manners they stopped doing it 