I'd skip the soffits completely if you can, or do minimal height ones if you want that look, or need them for wiring runs or other uses. Not having soffits will make for an easier go of balancing screen size/height versus riser height/low ceiling.
I am working with a 7'1" height (6'4" at the soffits) and am far enough along with the build to know the room will work quite nicely.
I don't know where you need access above, but have you considered something like large access panels that are played up as ceiling design elements? Maybe a star ceiling based access panel, or a couple of stacked mdf panels with stepped edges? The panel could even have a gasket and use GG between layers to give some isolation that a dropped ceiling would not offer you.
A little creativity will go along way in a tight space.
I am curious as to what you need access to, in the ceiling? Things like an exterior water shut off/drain valve might be moved to another access point. A show I saw last night had a water shut off valve moved to a kitchen cupboard above the finished basement as they didn't want an access panel in the finished basement.