I would not be happy with this.
My social but sensitive DC would find it weird and feel left out / ignored / unwelcome, apart from anything. Also, my 6 and 8yo bedtimes are 8pm, with at least half an hour's supervision and story-reading required. That clashes precisely with final prep, guests arriving and sitting down to dinner. Mad stress, unless these hosts are very, very chilled and very well-prepared (the evidence of the date clash implies chilled but disorganised, so much rushing around, delays and lateness). Plus, if not asleep, they'd be getting up and sneaking downstairs / to the top of the stairs to spy on proceedings, so would either need to put back and sat with in the middle of dinner, or set up for a late night with a DVD in another room - but how late? They'd still need to be put to bed and even at 9-10pm the dinner party will not be over.
Clearly your friend meant something different from you - your DC were welcome ot come to her house and fit in with whatever her family were doing for a weekend. Not that she would devote her attention to your DC for a weekend. Yes she's made a mistake with the clash but, if she meant the latter, she'd have blocked out that weekend in her diary the first, or second time you'd arranged it with her.
She wants you to rearrange.
Having said all that, it depends a lot on your and your DCs' relationship to her and her DH (if there is one) and her DCs (if there).
I have one friend, with teenage DCs, who would and could pull this off and, despite drinking etc, I'd be ok with it. That's because I've known her for decades, my DC knows her family, is comfortable in her home, her teenagers are great with younger DCs and, crucially, she's both organised and relaxed would have a plan; for feeding and entertaining the DCs and getting them to bed and would be able to prioritise them enough, despite having other guests.
So, it depends.