Besides plantaginea and her progeny; what hostas will tolerate sun from 8-12pm?
I'll have easy access to water to keep them nice and moist.
Most of them will under those circumstances. Since this a foundation garden, the shade will be made by the building which is different than shade from trees. You may have some blues that have melted wax under that exposure, but other than that or medio variegated white plants (even some of those like Americana might work), you should be fine. I would try Great Expectations with this exposure.
Every plant I've known loves East exposure w/ enough of water. The blues might loose their waxy coating but will thrive, none the less. Perfect!!
ALL OF THEM ...
the only sun that is of concern is about 2 to 6 pm.. sun during the HEAT OF THE DAY ...
some hosta can NOT pump enough water to get thru the heat.. with sun shining on them.. and just like you and me.. they sunburn ...
go for it ..