PS I don't know if this is of any help, but upon closer examination of the Apple Russian keyboard printing, I see that the characters at the right side of a key are not intended provide info about option/alt characters. They are simply an indication of where the keyboard produces something different than the normal or shifted English layout.
So on the number row, the "№%:,.; to the right of 2345678 are supposed to tell you that in shifted mode you get these instead of what is printed above the numbers, namely @#$%^&*. You see the same kind of thing on the keys for бю/хъёэж, but there it tells you what you get in unshifted mode (instead of what is on the lower left side of the key).
I have no idea why Apple chose that system, but I think it has been this way for many years now.