Upvote:2
An ESTA or a B1/B2 visa only grant the right to present yourself at the border to apply for admission. They do not need to be valid for the duration of the stay - only at the time of entering the US. In other countries, visas have to be valid for the whole stay, but that is not true for B1/B2 visa and ESTA in the US.
The length of the admitted stay is also not dependent on the validity of the visa. Entering under the visa waiver program is actually worse here, as this typically means 90 days of allowed stay, whereas B1/B2 grants 180 days. However, the border officer may also choose a lower duration of admission. Regardless of the admitted duration, it should be clear to the officer that your daughter is not trying to live in the US based on her recent travel history.
In any case, there is simply no need to have overlapping ESTAs and B1/B2 visa as with the B1/B2 visa still being valid in August, your daughter can use that.
Upvote:3
I don't think you're right about the visa being unsuitable for this trip, though it would be possible to have a better idea about that with more information (see my comment above).
However, there is a way to deal with the uncertainty. Officers are not supposed to admit people under the VWP if they have a valid visa for their trip, so arrive with both and let the officer decide whether the visa is valid for this trip. Step by step: