This community has thought me so much, thank you in advance. 

I need advice covering an old brick wall. 

Context
We’re in a 110 year old house in Toronto Canada (cold climate!), double brick, plaster and lather. The wall is exposed to the element, (the other wall is not), and no overhang. You can see the attic (where it is cold) the brick was already deteriorating, the rest of it is holding up OK.

The house performed very poorly on energy (146 GJ), some winter days it felt like the house had no walls. We had no room to insulate from the inside (too narrow for stairways), and limited room to do it from the outside (narrow walkway)

After a lot of research and considerations, I did the unconventional thing, for our comfort and for the love of the planet, drill and filling the inside and outside wall with Air Krete. 

It’s been a year since the fill, and we got to 110 GJ (from 146), and we feel the difference in the winter, especially from an air sealing perspective, it has been very effective. And we were only able to do 70-80% of the walls. 

Comfort and energy reduction goals achieve! I am happy here. 

Now I want to protect the brick, given the gap between the double brick wall  has been filled with Air Krete, I am concerned about driving rain and moisture being trapped and potentially causing damage during thaw cycles. 

The added insulation from inside likely could make this worse (as I have have learned from this community). Although at best we got to R9 (2-3 inches of Air Krete)

I am considering the following options for the brick, and would like to know if this community has any advice: 

1. Siloxa Paint (Seal): repair the mortar and all cracks, seal it with Siloxa/siloxain

According to this article you get 96% reduction in moisture absorption while letting the brick breath

This would be the cheapest option, and gets to preserve the look of the house.

I am considered about it’s efficacy, will it do enough to protect the brick. 

https://www.sciencedirect.com/science/article/abs/pii/S036013232100250X

2. Siding: add furring to the brick and overlay siding with wood looking vinyl, a bit complicated given all of the wiring and utilities, but not impossible 

3. Stucco: a more expensive option, but maybe we can add in a bit of insulation so there is a win, but not a ton given how narrow it is

4. Cork Paint: there is very limited data on this product, and sounds too good to be true, but an option to consider
https://www.thermalcorkshieldbc.ca/

Any advice from this group? 

If not, who is the right professional to get advice on this from?

Thank you in advance for your wisdom