I got my Jem'Hadar BO reward and added him to my crew. A quick trip back to starbase and I go tot he tailor to get his outfit in line with the rest of my crew...

but the "Modify" (and even the rename) are grayed out and non-selectable.

Is there a trick to re-outfitting my new BO or is he stuck in the uniform he came in?

you can't modify it
Same with Photonic Science from referral program
Same with Borg Science from khitomer accord
Same with Reman Science from romulan fe
Same with Breen Tactical from breen fe

Their reasoning is it would be too much work on Cryptics part making them fit with every costume.

i understand that we cant change uniform but Cryptic could give us chance to change colors? is to much to ask?:p

This is the reason the only special BOFF I have comissioned is the Borg preorder engineer.

Are any of these still available, aside from the JH BOFF, or have all of these FE's ended?

They are only available when Cryptic releases the replay of the FE. When they do all special gear an BO are available.

Apparently. I would also add to your (and the OP's) complaint that all the special BOs are male.

Short answer is, LAZINESS!

You should be able to pick up a Breen on the exchange.

there are no Female Jem'Hedar