You're right, you'll find differences and omissions between different references, but you should be seeing a common thread emerge. To link a couple of the ideas tossed out here, it will be a combination of having one or two simple references to rely on and applying common sense.
Medicated feed? The medication is amprollium which is for coccidiosis. If you are buying your chicks already vaccinated for cocci do NOT use medicated feed. It will nullify the effect of the vaccine. If not vaccinated for it, it's your choice medicated or not.
Grit, not necessary immediately and for as long as their diet is limited to crumbles. You'll want to think about supplying grit in advance of introducing them to leafy treats, as the grit is what grinds up the long fibers to alow the to pass further and be digested uneventfully.
This would be different stuff from the various vitamin/electrolyte things like Quik Chick and others. Those can be handy to have on hand for newly arrived chicks who may have had a hard trip. Indicators of stressed chiks in the box wold include (obviously) dead or noticeably lethargic birds. In such cases it is important to introduce them to water directly, and if that water is charged with one of the vitamins/electrolytes, all the better. Check the packing date and time which will be printed somewhere on the shipping labels. If the trip was a full two days or more and the chicks are stressed, it couldn't hurt to add sugar to the vit/elec/water mix for the first couple of days at he rate of 2-3 tbsp/gal of water. I also keep a pack of Gro-Gel on hand. Another vitamin/electrolyte product, its fine grained powder swells when wetted (immediately and impressively) into a green gel, particles about the size of crumbles. The green color is attractive to the chicks and gets fluid into them as they peck at it, even if they are not figuring out the water source you have provided for them. Some hatcheries actually mix some up and put it in each shipping container to help the chicks on their trip
Once in the brooder and stable, follow the reference of choice.
A couple online references of a handy length are
http://www.mypetchicken.com/backyard-chickens/chicken-care/chapter-4-caring-for-baby-chicks.aspx
http://www.mcmurrayhatchery.com/chickcare.html
In the case of the McMurray link, heed their caveat that if your birds are going to be Cornish cross meat birds, they will need to be fed differently after the first 1-3 weeks. A good reference for that is
http://www.welphatchery.com/cornish_rock_care.asp
There are others. Some find the Guide to Raising Chickens by Gail Damerow (part of the Storey imprint's seres on how to raise all kinds of critters) helpful to have on hand for everything from coop design to care of chickens of all ages. It's worth the price, especially if you're new to the endeavor.