A further update: I have been referred to the AvMed Complex Case Management board because of my congenital cataracts. I'm not too surprised, it's pretty rare for a kid to have cataracts. However it adds another couple of weeks at least to a decision or the next step in any case.
I'm starting to realise that RAAus RPC might have been the way to go anyway (which doesn't require the CASA Class 2) but I will still see this process through to the end since I've sunk a fair bit of money into the affair (second pair of glasses, medical, ophthalmic report, CASA processing fee). Also, if I am successful I don't think I'll face the same barriers every 4 years as my condition is completely stable and I may want to get RPL or PPL in future (though reading some of these threads in here makes me wonder if it's worth it!)
Hope this info shows up someday for some "Cataracts Kid" like me when they do some Google searching on cataracts and medicals in the future.