What I usually do is surround my own text by unquote, then quote, like this (replace parentheses by square brackets):
(/quote) inserted text (quote)
At any rate, yes, optical (TosLink) would be the best audio connection.
People have different thresholds for what they consider usable. Most of the apps are free, so you could try them yourself,
The most common networked audio and video file service protocol is DLNA, You could consider installing a DLNA server app. Others will have to provide more info: after a brief tryout of DLNA and its various limitations, I decided to stick with a direct HDMI connection to my laptop.
I dunno if your router will provide networked access to a directly connected hard drive. You'll have to check the router's manual.