YES I AM A FILTHY NET-LISTER AND HAVE BEEN FLYING FAIR SHIP REBELS BECAUSE IT'S GOOD.
(And I have a sick customer TIE Fighter that needs to be on the table like all the time, but suck at crackswarms,hush! :P)

Now with that confession out of the way.

I usually fly four ships in a pinwheel formation so I can get them into spots where my opponent would not expect four ships to fit and it has worked well for me so far.

Are the any good alternative setups other than Pinwheel and Box/ Offset box that can be used in a Range 1 synergy-heavy list like this?

How would you set this up against different lists like Triple Defenders, Rau-boats, Triple high agility aces etc?

Hmm.....

Good question, well put.

The easy answer, as noted, is a 4-box pinwheel. The problem is what you do when your opponent declines to fly straight at it.

You have a slight issue with dials - in that the single hardest ship to keep in formation is Rex's TIE fighter. Fortunately, it's also the one ship which doesn't really need to be in the formation - you can have the TIE fighter running free and it works fine - if your opponent wants to turn to engage the TIE rather than the block of three ships coming in from (now) his flank, that's his own stupid decision. Rex doesn't need to hit to trigger his ability, and is unlikely to do much damage anyway, so just evade and irritate people with suppressive fire.

More importantly, not chaining Rex to the formation gives you a ship with a good dial and barrel roll to act as a blocker.

Splitting up the other three is probably less useful - yes, you gain more board control but their abilities start to unpick.

Generally, you want Jess at the front. She's the toughest of the three (good) and that puts Biggs potentially at range 3 (good) and/or in range for some attackers and out of range for others, splitting fire (which is generally better than biggs drawing all of it). Plus, putting Braylen further back makes his gunner/R3-A2 arc harder to avoid.