i've kept 3 pairs of different species in a 240 (cinnamon, saddle, ocs) - the cinnamon female has gone thru several phases of trying to recruit the other species males to her harem (with some truly odd results) but she is the only clown that ventures more than a foot or so away from its chosen anemone 'home base'.
to some extent, it's gonna matter how the tank is set up (how the 'line-of-sight' is, more importantly, how many breaks in that line of sight are there) and the individual personalities of the fish involved. is your existing saddle female under the impression the entire tank belongs to her, or does she stay within a foot or so of her chosen home?
if you're willing to go thru what might be necessary to trap/remove any problem fish, it's worth a try. a tank that size, it's no easy feat, but...if you're up for that potential down the road, i don't see why not.
sounds kinda odd, but of what you've listed...i'd be most leery of the single fire clown. not because of any species traits, but just my experience that in multi-pair setups, the 'odd man out' unpaired fish starts a snowball of aggression (receiving it, or initiating it, but it starts it all the same).