Those issues would not make him turn into a singles hitter. If he's able to hit .270 it means these weaknesses are not a flaw exposing him against ML pitching, and that means he will not struggle to hit for power.
If those numbers indicate a weakness that will be exposed, it means he's gonna be hitting .220 and not putting enough balls in play for his power to make up for it.
Also a 27% whiff rate is above average, and not at all a red flag for a 21 year old in AA. He's a power hitter, he's gonna whiff a lot. Since he's a 1B the bar is really high for what his offense needs to be in order to be a real impact player, and he's probably never reach that level.