I'd vote for all the kids on the floor on single-mattress airbeds, if it were me, simply because each kid deserves her own space and not because of suspicions of the mom. But it sounds kind of like you think she is going to molest the children, or are you saying you think she is in some way going to be too needy and this will distress the girls? If you can keep the conversation on the simpler level (every kid needing his or her space) you might avoid a fight over your suspicions. You and your husband should provide the air beds, they aren't very expensive in that small size. If you are really concerned about molestation, the kids being overnight no matter whether they are in her bed or not is a bad idea.
The children would be seeing more of their mom ,thats a good thing ...what does their Dad say about it,?
does he have the same suspicions ?
We would like them to see their mother more often, but we also want it to be a healthy environment. The fear we both have that is the most real fear is that she is very manipulative and makes the children feel guilty when they are not with her. They sort of have reversed roles in that they feel like they have to take care of her. The 9 year old always cleans the house for her, so my biggest fear of them sharing a bed with her is that the dependency issue will grow.
I am new to this kind of site, how do I get an expert opinion on this as well?