Is it possible for wind driven rain to be forced into soffit vents?
Yep, that's perfectly plausible. You're saying that there's only wire mesh in the soffits -- not actual metal soffit vents? That would be the first thing I'd fix. The louvers on the soffit vents make it much harder for rain to blow up and into the attic structure. The second thing you might consider is then putting soffit baffles in ... they may make it harder for water to blow up into and across the attic space, and are generally considered a good idea anyway.