It is important to keep in mind that although your child will be sleep-trained there will be regression in one form or another, once new milestones are reached, understanding that babies usually try out their new skills until mastered which is usually 3-5 days is crucial.
When your infant begins to roll over once they are sleep trained its best to allow them to figure out how to get themselves back to sleep on their own. You can assist them during the day by allowing them to spend time in their special place (their crib). If you find that they become stuck in a position they do not like, then you can assist with teaching them how to roll from one side to the other. Helping them during the day will make them confident to do so during the night if they happen to wake during the night due to being in an uncomfortable position.
When your infant begins to sit up in the crib once trained it may be possible that they become stuck in that position trough-out the night so the best thing to do is teach them how to get back down on their own. The best time to do this is during the day. Once they know how to get back down you will not have to worry about them being stuck through-out the night. If your child regresses a bit due to this new milestone my best advice to you is to let him/her work it out on their own as long as they are not in distress.
As with rolling over and sitting up, standing up is another milestone your baby will reach. When this happens and your baby is sleep trained again your best bet is to teach them how to get back down during the day so that when it happens at night they won’t get stuck.
Note: It is better for your child to work things out on their own if they wake through-out the night. if he/she seems to be overwhelmed than it is ok for you to help him/her out. One thing to remember is consistent helping out may introduce a Jack-and-Jill effect (the baby gets up and you put him down and this continues through-out the night and can introduce unwanted habits) Also, at this point it is recommended to not introduce any sleep aides or assisting the baby with falling back to sleep.