For this age of chicks and without a broody, yes - I would soak the feed overnight. Do it in small batches - just enough to feed them all in a day.Its warm. If tou put your hand in it’s comfortable. Some places are cooler others warmer. Will making a mush help them in digestion?
It will help soften up the corn a bit but they still need some grit to help process that efficiently. Do the best you can in picking out the largest pieces of corn. As they get a little older, they shouldn't have a problem handling those, but they are only a few days old right now.
If you've never had issues with feeding that feed, then I would almost assume that grit is added, but it wouldn't hurt to provide a small amount of course sand if you have any.