I'd say you're on the right track... make sure the OD of you collector will fit the 18deg bend you get (the bend should fit OVER the collector)
Also make sure the bent bit will fit onto your muffler/silencer, too! Order the appropriate size muffler so that the pipe goes INTO the muffler end (HINT: It will be about the same size as the bent pipe OD
).
Have them include some stainless pipe clamps like the ones in my post you linked. They are VERY strong and will cinch things up.
You might consider cutting some short cuts into the extension pipe/muffler so the ends can compress tightly.
You can also CALL THEM UP! Tell them what you need and what you're doing, they will put together a parts kit for you... I'm sure of it. They were awesome to deal with over the phone when I called.
And good call on getting that bracket. You'll just need a bit of strapping from your Right passenger peg mount to hang the muffler from.
If things don't just slide together (which is entirely possible!) take everything to a muffler shop and have the parts expanded slightly to fit.