I would second seeking a comprehensive neuropsychological evaluation. If I am understanding correctly, most of the diagnostic information you have comes from OTs. As much as I love the OTs I've known and worked with, honestly, it's a field rife with diagnosis and treatment protocols that are, shall we say, not evidence-based. And, of course, the concerns you have are much wider than those falling within the expertise of an OT.

...pronounced like the long vowel and first letter of the alphabet...