Will it work OK rear shimano mech and SRAM shifter ???

no

no they have different cable pull ratios

I wouldn’t try that, recipe for disaster in my opinion.

Unless you do the sram 9speed shifter to shimano 10 speed modification in which case yes.

SRAM shifters with names e.g Rocket, Attack work with Shimano mechs

Numbered SRAM shifters only work with SRAM mechs

9sp SRAM shifters can be made to work with 10sp Shimano mechs

OK thanks saves me messing it up

I have MRX and Attack shifters on a couple of my retros and they work a treat.

The problem is the price, Attack 3 x 9 are very expensive and I got mine from Germany in the end, as they were much cheaper.