Is the max number of initiators for an initiator group still 32?

yes the limitation is 32, but that's 32 elements. The elements can be either Initiators, iSCSI names or other IGs for the cascade.

So you may use "parent" IG and "Child" IGs which each Child can contain 32 Initiators.

Then you may create up to 1024 initiators in one cascaded IG: 32*32 = 1024.

Just be reminded that Child IG can't contain its Child anymore.

An initiator group may contain a maximum of 64 initiator addresses or 64 child initiator group names in vmax 3

Hello, you can see "Article Number 000458972":

Initiator Groups:

• An initiator group can contain up to 32 entries, (Fibre or iSCSI) on VMAX2.

• An initiator group can contain up to 64 entries, (Fibre or iSCSI) on VMAX3.

• There can be up to 8K initiator groups per VMAX or VMAX2.
• There can be up to 16K initiator groups per VMAX3.

• An initiator group may also include the name of another initiator group to allow the groups to be cascaded to a depth of one.

• An initiator group can be added to another initiator group (cascaded group), only if it does not contain any initiator groups (that is not already cascaded).
• A parent initiator group can have upto 32 child initiator groups on VMAX2, and each of those child initiators groups can contain upto 32 initiators.
• A parent initiator group can have upto 64 child initiator groups on VMAX3, and each of those child initiator groups can contain upto 64 initiators.
• An HBA may only belong to one initiator group, but may have masking views for both an upper and lower initiator group if cascaded.
• There can up upto 4K LUN addresses per initiator group. For cascaded initiator groups with Consistent Lun enabled, the 4K limit applies the entire "family" that is The Parent and ALL Child initiator groups. See Solutions Enabler: Creating a masking view on VMAX3 fails with: "There are no available lun values" for details on Consistent Lun enabled initiator group LUN addressing limit.

Note: For VSA (Volume Set Addressing) enabled Initiator Groups, the LUN address limit is 2K. That is because HP-UX can only address to Lun Address 7.