System configuration advice please

[fitz1985]

Hi All, looking to tap some of you talented chaps to check my options / thought plan

Setup.

TV: Panasonic TX-40AS640
AMP: Arcam AVR 280
Bluray: Panasonic DMP-BDT220
Tuner: BT Vision box (current)
Fronts: KEF K160 floorstanders
Rear: Mordaunt Short Pearl 10i
Center: none
Sub: Tannoy 10"

The Arcam doesn't do Audio over HDMI, and I'm thinking that the hdmi spec on it, even though it is effectively just an HMDI switch would mean I wouldn't be able to take advantage of 24P and Deep Colour that the bluray player will support?

Currently I have the Vision box plugged into the TV via HDMI, and its optical out into the amp. I like this as if i'm just watching tv I can use the tv's speakers, and then use the amp if there is something I'm bothered about err, 4.1 sound on.

I plan to do the same with the Bluray to take advantage of deep colour etc.

Also plan to use a Raspberry PI 2 with rasplex to do some streaming, both dvd quality stuff (use the player for blurays) and FLAC audio. I'm thinking of getting a hifiberry digi+ and sticking it into the amp via optical / Coax.

Now my questions!

- Is there any advantage / disadvantage to me using the optical out of the TV and stick that into the amp. I had to do this playing a Bluray on the PS3 the other day as for some reason it wouldn't play audio to the amp via optical (but there was data going over the optical). I could just keep the amp on the same input then, and not run out of opticals (only 3).
- Is the above solution for the PI going to result in lower quality audio, than using hifiberry to punt digital to the AVR and then using its high quality DAC to decode?
- I presume doing the above to make use of the Arcam DAC is going to be a better option that either a) the hifiberry DAC and analogue cables to the Arcam. b) using the HDMI to the TV and then the TV's optical out.

I'm not overly fussed about the surround sound being perfect - its a narrow room, and to be honest I'm not keen on changing anything much, just making sure its hooked up in a way to make the most of it. I would however like the best possible outcome - again using the kit I have really, to get my music playing at its best. The AVR has a PCM Stereo mode for the digital stuff - I presume this is my best bet short of coughing up for a high quality CD player / Streaming DAC etc rather than the PI?

Sorry for the ramblings..any thoughts are much appreciated.