Also does it matter which brand of electrolytes I buy?
I forgot to mention this part. My go-to for this is clean water. I consider it essential that their water is not allowed to get dirty. If they poop in it or scratch bedding in it, the water needs to be changed at least once a day. More often does not hurt. I don't know how you plan to water them, if you use nipples this is less of a concern.
Whether straight from the incubator or the post office I do not automatically add any supplements to the water just because I can. I haven't seen the need and I tend to do things by need. A couple of times I've had a weak individual chick. I treat the individual. Instead of buying special electrolytes I feed some hummingbird liquid to the chick to give it a burst of energy. I use a medicine dropper to put drops of liquid on the tip of its beak. It will swallow them and I'm not risking forcing liquid down the wrong way. The sugar is essentially the same as the electrolytes and I always have hummingbird liquid on hand.
If I received a shipment of chicks that had a rough shipment, say they were delayed a day, I would supplement their water, probably by boiling some sugar in the water to dissolve it and then cooling the water. To me that would be a reason to do something. I've never had a problem like that in shipping.
There is nothing wrong with giving them the electrolytes. It will not hurt them. I just don't consider it to be necessary without a special reason. If you do give them some, read the instructions on how to give that specific one. Some may say to only give them once. Some may say to dump the water and clean the container after a certain amount of time, I've read 12 hours for one supplement. Some may be fine to forever give them.
As far as Flock Raiser, All Flock, Starter-Grower, or some other marketing name, the name isn't that important. What matters is the analysis. The two critical nutrients are protein and calcium. Calcium needs to be low, a lot closer to 1% than 4%. The protein is whatever level you want. If you look at the analysis on the bag label you'll see that all the others are essentially the same. Whatever is available at your feed store will do fine.
If pellets is all you can get, the pellets are too big for baby chicks. So put some in a blender or food processor and reduce the size. I've had to do that. Try to not reduce it to a full powder, it's "best" if it is still in chunks. If you reduce it to a powder the ingredients can sort themselves by density so the chicks may not get a fully balanced diet. Of course there is a fix for this. Wet the powder to turn it into a paste. Just make sure they clean it up so it doesn't last long enough to go sour.
Does softening it negate the need for grit, then, too?
When it is manufacturer they gather all the ingredients for chick or chicken feed and grind them all together. If they sell this as a powder, it's called mash. To make pellets they wet mash to turn it into a paste, extrude it through a die, and flash dry it. This is pellets. To make crumble they crush the pellets some. So the ingredients are the same in all of it. And it was all powder once. Since it has already been ground there is no need to give the chicks grit if chicken feed is all they eat. Pellets and crumble will fall apart when they get wet with digestive juices let alone get crushed in their gizzard.
If you feed them anything other than mash, crumbles, or pellets they do need grit. This means grains, grass or weeds, kitchen scraps, bugs, just about anything.