Prepping external bare brick wall for tiling

Chasing some tiling wisdom, tips and tricks from the tiling community...

I have an external 2x bare brick wall 3m high x 2.1m wide double brick that I need to prepare for tiling 900x450 rectified porcelain tiles. The are blade feature walls at the entry and tiles on all faces x 0.3 sides.

- If brick work is uneven, what is the best easiest and cost effective way to prepare it? Can I fill low stops with adhesive or other recommended fillers?

- Can I put adhesive onto bare brick or should it be sealed/primed first like Bondcrete? My thoughts are it would bond best to bare brick if cleaned thoroughly first.

- As the wall is out in the weather, does it need to be thoroughly dried out first after rain or is some minor moisture ok?

- What adhesive do you recommend for exterior use in full weather? Can I use Davco SMP Evo as I've used it before inside and have a 20kg bag left over?

- Are 2mm grout gaps acceptable practice?

- What is the going rate per square metre for installing rectified tiles vs normal tile As I know they are more challenging/time-consuming? I might have to call in a pro but am confident I can do a good job and save money for my friend!

I will mark out tile pattern thoroughly before hand and hi/low spots and take my time. I have use of a power tile cutter and will mitre edges and us levelling system to help reduce and risk of lippage. I have tiled before and turned out great but I know rectified tile will be a challenge. I love a challenge...

Any tips or advice is much appreciated.
Cheers