I would make sure there are no termites, and give them all a good coat of primer and paint, and then put up new soffits. Birds roost in them, and make a mess down the side of your house. Bees put nests up in them. They are a nusiance, which is probably why they were covered over.

It looks to me like it's a combination of a little dry rot (which is really wet rot) and a lot of butchering in order to get the soffit to fit. I have exposed rafter tails and like the look. If you want to repair yours, you'll have to maintain the structural integrity of the overhang, which is created by the rafters being continuous into the attic. You could add new wood to each side of the tails, but that could look clunky. You could try to cut each tail off the same and attach a new bottom: very labor intensive. Some kind of cover?

I'd peel the facia and set up a fence/jig to cut the rot off the bottom of the tails. Fit and adhere replacement wood, prime and paint. Maybe a little Abatron for the smaller spots.