I also faced weird problems with Oracle ACS engineers for Exadata. They actually follow what ever was thought in the training.
for our site, he could not even create the other mount point (After reclaiming the other OS space).
I am sure you can install the Grid Infra and RDBMS in any other mount point.
You can have any mount point for installation, not particularly /u01.
The OFS (Oracle Flexible Architecture) suggests to have oracle home as
In case installation is invoked through scripts and if script demands /u01 partition, then you need to check.