I hope I got this right

Weren't these questions answered in your other thread?

http://www.avsforum.com/avs-vb/showthread.php?t=1354162

You have been slightly misinformed and here is why. Rca cables come in lots of colors and plug into lots of different ports. Some are analog and some are digital. You described the color but not the port. The red and white cables won't carry a digital signal. The yellow composite cable and the red/blue/green component rca cables will carry digital. Instead of "lossless" think and say "digital". For now you want 5.1 digital sound passed from the bluray to the stereo.

If you are connecting only a single red and a single white cable there is no digital anything going on. Download a manual for a mainstream home theater receiver for free. In that manual every basic cable and connection is explained. Are you willing to try another audio connection besides red/white rca? Until then not much more we can do for you.

Hello,
Sadly, you have been given faulty information as neither Optical nor Coaxial will support any of the Lossless Codecs. Provided both your BDP and AVR have Multichannel Analog Outputs, you can get all of the Lossless Codecs. Do realize that when using MCH, the Volume level will often appear lower than say a DVD connected via OPT/Coax at the same Volume Setting, but when Level Matched will sound quite good.
I would continue to listen to DD/DTS via Optical or Coaxial.

Even if your AVR does not have MCH Inputs, you can connect 2 Channel RCA's and get the 2 Channel Lossless. This is assuming that you do not have an HDMI AVR/SSP,
Cheers,
AD

S/PDIF whether optical or or coaxial, when sending PCM is inherently lossless, because PCM is inherently lossless (unless we start nitpicking about digital being inherently lossy due to sampling, but let's no go there.)

This has always been the case.

When people say S/PDIF does not support lossless, they mean lossless compressed audio. That would be Dolby Dig. or DTS.

HDMI support lossless compressed such as TrueHD.

Analog, would be considered lossless, so if you have multi-channel analog out (8 channels is required,) you can get lossless.

If you connect your Blu-ray player to a receiver, you have a number of options...
1) Stereo Analog (Red/White RCA cables) - If the player is decoding lossless audio, you could call this lossless. But you will get a downmix of the surround sound - if that's what you want, great
2) Multi-channel analog (8 single RCA cables, or whatever) - Lossless sure, but you need a receiver with appropriate inputs; In this case, I assume there's no downmix, you would would have a 7.1 speaker setup for proper audio
3) HDMI - Pretty much works with any speaker setup
4) S/PDIF - Pretty much works with any speaker setup; Very high quality from Blu-ray (640kbs for DD, 1.5 Mbs for DTS); Could be argued that it would be hard to hear the difference between this setup and lossless; Certainly a simple way to connect, except that HDMI is a one cable audio/video solution

Lossless and lossy refer to types of data compression. dts-MA and TrueHD use lossless compression, meaning the PCM output from the decoder is identical to the PCM that was fed into the encoder. DD and DTS use lossy compression, meaning some of the original PCM is not restored when the file is decoded.

It is not correct to call PCM lossless because there's no data compression involved.