Dear Niki,
There is no perfect answer that I have found, but I think there are some things that help. For sitting still, I recommend using a "wiggle seat" cushion on the chair and tying an exercise band around the front legs of the desk chair for the student to push against. Both of these allow for stimulation while seated. I place my student in a special place in the classroom, either at the back or to one side and next to students that will help her be successful. I choose the back or side because 1) it is easier for the teacher or assistant teacher to offer help or redirection as needed and 2) she may stand behind or lean on her desk while working without bothering other students. As for standing in line, I think the child should be assigned a "success spot" in line, preferably in the front right behind the line leader. This makes it easier for the teacher to keep an eye on things. I would also implement a reward system targeting specific behaviors. For example, if you are trying to change the behavior of pushing in line, offer a reward or sticker for every time the student lines up without pushing. Put the sticker on a chart. When 10 stickers are earned, a reward is earned, either from the teacher or parent. Also, ask the teacher to communicate with you frequently, and make this easier by initiating the conversation. It is easier to reply to an email than to initiate one, so ask if you can send the teacher an email every Friday asking for an update, and then remember to do it. Then be sure to be grateful and say "thank you".

Hope that helps.

Also, I have found the Facebook group "Sensory Processing Disorder Support" to be much more active than this forum, so if you are not already a member, I would suggest joining.