Depends on if you can (or know someone local that can help) do your own audio system. Alot of the times you can do the same system or have the dealer do it for less than factory option. I personally would look at autoflow and possibly heater and do the stereo aftermarket and buy what you want!
Bow filler cushion is a small item so flip a coin. You can always add it later if you want but small cost so adding it now won't effect much. I personally like it but I have kids that spend alot of time in bow.
I don't like the sundeck walk over option but we use our sundeck alot. Wife loves to lay on the back and sun. Just have a "no shoes" policy and problem solved.