The Corsair CMSA4GX3M1A1066C7 memory module is not specified as being 2Rx8 in the provided sources. However, it is a 4GB DDR3 SODIMM module, and typically, such modules are configured as 1Rx8 or 2Rx8, but the specific configuration (1Rx8 or 2Rx8) is not explicitly mentioned in the available information. To confirm the exact configuration, you may need to refer to the detailed specifications or contact Corsair support directly.

No idea. I bought Corsair memory for my late 2009 iMac.

Yes, they would fit the late 2009 iMac up to max. 16GB of RAM

Yes, these are the right RAModule for this MacBook.

I haven't found anything on corsair, but as an alternative, take a look at this link: https://www.kingston.com/de/memory/search?DeviceType=2&Mfr=APP&Line=iMac&Model=71472

hello no unfortunately still