An update:
I met with my accountant this past weekend and discussed the Medical Expenses Tax Credit issue. He had taken the time prior to speak on the phone with the CRA offices and happened to connect with an enthusiastically-helpful gentleman there. That guy didn't have all the answers himself but did bring someone else with direct experience on the issue into the conversation. They confirmed that all the treatments and costs I've incurred would be allowed for submission so long as they were sanctioned/prescribed/referred by my doctor. With a letter from my doctor clearly stating everything I was doing was considered "medically necessary" by her in the treatment of my gender dysphoria, and receipts are available for all of these amounts, the case is virtually iron-clad.
I met with my doctor today for the express purpose of obtaining such a letter. She had never written one for this exact purpose before, but after a bit of discussion to clarify the language, she wrote up and signed the letter. I now have everything I need compiled and will be submitting the documents to my accountant shortly. I've had the benefit of dealing with this one family doctor and LGBT health program at Sherbourne Health Centre from the beginning of my transition, so all of my activities have been documented, condoned and supported by them from day one.
There is still potential for the CRA to dispute some or all of the items in question, particularly whether or not they will accept the surgery travel expenses. My doctor included in her letter that I had justification to travel to Montreal for my FFS surgery because it is one of few locations in Canada where I could locate such a specialized surgeon. One additional piece of documentation I will be including is the guidelines from the surgeon because it states very clearly that I required a companion present in order to be allowed to leave the hospital. The travel costs for the companion are also valid for submission in this instance, and this will greatly simplify allocating costs from the receipts since most of them were not explicitly divided between me and my Dad (who went with me).
I have the benefit of my accountant actually having worked for the CRA in the past before he moved to a private accounting firm. While this was long-enough ago that he's never dealt with transgender medical expenses before, he does still know the CRA operation pretty much inside-out. He knows how they work and talk, and he knows who to speak to and what to say in order to have effective and efficient interactions with them. It gives me a lot of confidence in his word that my submissions actually stand a good chance of succeeding. He said that initially upon submission, none of the 'accessory' paperwork even gets looked at by the CRA because the tax return is being filed electronically. The only way a dispute or detailed investigation comes up is if the tax return later gets flagged for audit.
One last thing to make clear - expenses must be submitted for the tax year they occurred in. As such I will be putting through the ones for 2015 alone right now. (Thankfully this represents the majority of my overall transition expenses to date.) Anything I have for prior years requires submitting a request for an adjustment to that particular year's tax return. Expenses I incurred prior to 2014 probably aren't worth enough to justify the cost of the accountant's billed hours to assemble the application. Expenses for 2014 probably are worth enough though. I will wait to see the outcome of my 2015 tax return before attempting a 2014 adjustment. If 2015 fails, it's not worth pursuing. If 2015 works, however, then the precedent is set which pretty much forces the hand of the CRA on any other year before or after. The approval on the grounds of Gender Dysphoria is kind of an all-or-nothing shot - If they approve one particular procedure as medically necessary then they have a very tough time rejecting any of the others.
