Hello BLINGMW –
When I got my 2014 BEV in 2014 I purchased some lowering springs and took it to a local suspension specialist (they set up BMWs and Hondas for track use).
Having never seen an i3 before they did tell me that they found the suspension design to be similar to other BMWs and they asked if I had a camber preference which I answered "yes" and asked if they could set it to slightly more negative than stock.
Having looked at my records from back then, I don't have notes about the stock camber, but after installing the lowering springs results from the alignment rack were:
Front -1.1º camber, 1/16" toe
Rear -1.6º camber, 3/32" toe-in
(I agree these notes are a bit incomplete, but the mod was done back in 2014 so that's all the information I have).
BLINGMW, I'd suggest finding an enthusiast-oriented shop and bringing your car to them. It's likely yours will be the first i3 that they've ever seen.
p.s. Just another thought, have you searched for i3 camber plates?