For the grit I'd mix chick and grower/pullet together, stick it in a dish, and let them pick out what they want. As they get bigger you can toss some adult size in there too.
As far as the layer feed, really give it a good look/sniff before using. If it looks off in any way, better to not use...
You're already at the point where they're almost too big for chick grit. I provide grit as soon as I get chicks, so 2-3 days on. By about 8 weeks they're on small adult grit.
For grower, you can either switch according to the bag's instructions, or do what I do and feed stuff until it runs...