You absolutely need to wet the hay, no way around, especially roundbale hay. Get a slowfeeder haynet, fill it and soak it in a tub or wheelbarrow, dump the water, let it drip out a bit and hang it up. If you have two or three of the nets, it's even easier, do the one for morning the evening before. Or, other possibility, get a roundbale slowfeeder net. Key is that horse cannot bury it's head in the bale to pick the best leaves and meanwhile inhale all the dust there is. This net will also eliminate a lot, if not all wasted hay and pay for itself within a couple of months. Nice side effect in my book
As for hardfeed, any feed is fine as long as it's given wet/moist.
You'll have to eliminate dust and mold, it you s THE most important thing, no way around.