B.S.
I've been a child care provider for 20+ years, have raised two daughters to adulthood and have four wonderful grandchildren. So, I've had lots of potty training experience : ).
A lot of people use the system you suggested...no pampers. Also, things will be different if you can get the two older boys to take the youngest one to the bathroom with them when they go. It works well in my daycare. An older child helps set the example.
The main thing is to be encouraging. Once you start it...don't stop. Be consistent. You can even use pull-ups at naptime, bedtime, and on trips in the car...but ONLY then...until the child begins to show signs of control.
I take a colored index card each day and at the top title it *Lauren's Potty Report*. Each day, it's a different color. I tape this in a special place out of the trainee's reach, LOL! Then each successful potty time they get to pick out a sticker to put on their report. Each and every success. A large colored star sticker represents the *dirty* deeds. The kids love it. It works well. One summer I had five 2 year olds to potty train. Our entire summer was devoted to potty talk, LOL!
Just an idea that makes things fun. Best thing about spring and summer is being able to let them wear less/no clothes.
Good luck and God Bless. Here's to happy training! : )