I used to be on an EC yahoo group that was pretty good, might still be active.
There are several books that I read, Diaper Free by Ingrid Bauer (and I have it listed on half.com! :) )and one by Laurie Bouck
http://en.wikipedia.org/wiki/Infant_Potty_Training_(book)
http://diaperfreebaby.org/that said, not sure if those will help you at this point.
help each child where they are at. if the younger one is more in tune with his body, go with it.
my kids were usually bare bottom at home. my kids liked the baby bjorn little potty and refused to use the regular toilet for many years, so ymmv on that. Id focus on offering them chances to go on the potty, suggesting they go when you go, being chill about it.
I didnt do an ec with my first, but she started to reject diapers at 14 months and was completely out of diapers and pretty much accident free from 19 mos on, but it was really all her. She would refuse to wear diapers and refuse to pee unless I provided the bjorn little potty.
my second, I did ec from the start. by 1 he was using the potty pretty much exclusively although at age 2.5 he developed a toilet aversion for #2. I still dont know why or what happened, but then for the next 2 years, he would only do #2 in a diaper, which we put on him for that purpose, once a day. it was so weird. he had no problems peeing in any potty.
my point is, you do what you do and they do what they do.
Id recommend reading about late start ec or early potty training, take the parts that make sense to you and feel like a good fit for your child, and try it. dont worry if the younger one gets it faster than the older one. every kid does their own pace. try not to compare too much, but help each kid where they are at.