Going Backwards with every little bit of Progress

Our 4yr old has a hard time switching any type of activity. I need more info on this problem. I give him warnings, countdowns, whatever I can to prepare him for activity changes. He will still go into a crying thrashing fit, and it doesn't matter where we are (think public tantrums at their best). I already try to not bring any added attention on to our bus load of children, but with a fit thrower it's inevitable. People stare. OMG! I must look like a crazy person. Oh well, it's my payback because I have done my share of staring. It's my turn to walk in those shoes. The good part is that we can reason with him, he isn't 100% out of control. So now we move on to the 1 yr old. He is very sensitive to telling him no, or redirecting him. He will throw himself down and scream, and not even for real reasons. Some days I think he is getting better, then he will get mad because I get him out of a drawer. Even giving him a toy and trying to redirect doesn't usually work. These behaviors are new for us to deal with and parent. I am using consistency and redirection. They are very sweet children, affectionate, and very funny. Visits with mom should start soon. I have mixed feelings about it, but I will support mom however I can.