no it won't work, well not perfectly - sram road and sram mtb derailleurs don't use the same actuation ratio - they're both marketed as 'exact actuation' basically because it's closer to exact than shimano and when rounded to whole numbers the ratio is exact or '1:1'. The decimals are different though. From memory:
SRAM MTB - 1:1.1
SRAM Road - 1:1.2
Shimano - 1:1.7 (or 1:1.9, can't remember)
any way, Rival rear mech with SRAM MTB shifters probably would work to some extent, but you'd be better off running a short cage X.9 or X.0
I read an article on shimano deraillieurs where cable location on the mech affected its leverage, connected above the allen bolt was a different leverage to under the allen bolt, i'll have hunt around for it.
This may well apply to the force mechs also.
Correct, putting the cable on the other side of the bolt makes the derailleur move more per shift - if you use a 9 speed shifter, and put the cable on the opposite side of the bolt the movement of the derailleur will suit an 8 speed cassette. Which is handy if you decide you want to run 8 speed but can't find any decent 8 speed shifters.