Rob and shoplifting are very cool but not pickpocketing 'cause there is low chance that you can pickpocket someone and the level needed for higher class is also high
Process is kinda slow or perhaps I haven't found any way for quicker pickpocket yet
All ATMs have equal chances, it is entirely based off of your level. All natural RND variance :) Also yes! Jumping doesn't serve much of a purpose but there are a few low objects you can jump, like in the dirty parking lot in the gangland, there are some pipes that can be jumped. Otherwise it's just for fun ;)
You can inspect the person's level before attempting to pickpocket them. Then, you need to follow them and continue stealing from them. The closer you are to the minimum level for that person, the harder it is to pickpocket. Then, it gets exponentially easier. For example, if you are level 1 and the person is lvl 1, then you chance of succeeding may be 5%. If you are level 2 and they are 1, it may be 15%, if you are level 5, maybe 50%. It gets easier and easier. So if you turn level 10, you may not want to rush to a level 10 person just yet. Level up a bit first. I don't call it grindy for nothing! It's a grind, especially at the early levels. Push through!