To be clear, it is the first round of production - not total. And in that, per my dealer "Currently 34 order slots available in the US….only 7 of which are not sold….and 3 of those are in 'Center Own Use' status which means don't call me you can't have it!"
As for the blues...
I think "Alpina Blue" is the standard blue you see on most Alpina's that aren't black. It is a cool color and screams "This is an Alpina". I wouldn't mind it of course, but I think the Mediterranean is a darker blue and would be even sweeter. Tanzanite is STUNNING in person and if you can get that for only an $1,800 up charge, then do it!
You are getting a special car, get a special color - that's my advice
edit: re the lower residuals, BMWs normally have a lower residual at the beginning of the model year production than at the end. I expect it will go up a bit.