You won't have any issues with this, as the maximum number of allowed logical drives on the controller exceeds the number of disks in the server.
I like to caution against doing this, as I have with Hadoop and ZFS solutions. Multiple separate RAID0 logical drives is not the same as having a JBOD controller. There are implications for hot-swap events because a failed disk really becomes a failed logical drive. This can cause device renaming issues at the OS level.
If this is a permanent need, I'd suggest using one of HP's purpose-built SAS HBAs, like the H220 (LSI-based)...
However, if you update the firmware on your existing P420i, you will see an option to create multiple RAID0 arrays automatically if you use the HP Smart Storage Administrator, as you're requesting. This was put in place specifically for this use case.
Auto RAID 0 – creates a single RAID 0 volume on each physical drive
specified, enabling the user to select multiple drives and configure
as RAID 0 simultaneously.