There currently 7 active SPP at the moment, I'm not sure that a...

There currently 7 active SPP at the moment, I'm not sure that a custodian arrangement would put up with 1 0, 20, 50+ shareholders requesting 7 seperarate forms in a single month as you say for $5 a trade.
And as they appear unwilling to talk over the phone even for a simple enquiry I wouldn't rate your chances of operating a SPP through them.

It may be worth emailing the SPP Harvester brochure to Superhero & saying this is what I'm trying to setup with you & you will get $1,500 broker fees upfront plus another $100+ p.a., explain the process you would go through & see what their response is. Let them know there would currently be 5 SPP's you'd be applying for in Jan.
Plus let them know you wouldn't be the only one trying to do this through them.

Personally I wouldn't even setup an account with them until you get a concrete assurance they will play ball & in a timely manner i.e. the timeline to get your SPP shares on your account from the issue date.