Well you cannot really train three different position players... I personally would make them all Centers with good secondaries, because none of them have enough OD or potential to do a lot with them. All three of them could however turn into decent bigs. Your second dude should be the basis of you training and you can trian the other two behind him. I would do a couple weeks of 1v1 and then go into ID and REB training until they get up to 10. From there I would go back into some more 1v1 training and IS training until IS is up to 9 on your PF.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs