Re a new monitor mix Jay? Not with that wee Bellringer! It is about as basic as you can get. It does however have FX sends, albeit to a mono FX out but this DOES give the promise of a separate balance to the cans. The "one ear" aspect can be avoided by using a mono to two mono jacks splitter lead. It should be mentioned tho' I think that having signal in just one ear can be very useful at times?
Now, at the risk of being a BOF...Again! This is an area where a bit of electronics nonce and a solder iron can reap vast rewards. Small boxes can be made to give each headphone user a choice of one or both ears. I understand the OP's desire to have two ear monitoring but for linking players it need not be "stereo".
Forgot! If anyone HAS such 'tronics nonce and a small "hi fi" amp it is quite easy to make it into a multi-headphone feeder. All that is needed is a feed resistor, 33 to 100 Ohms, depending upon the amp's power (but it is not that critical under about 100watts) per channel and per cans feed, and of course a rake of TRS jacks. Even a fairly feeble 20+20W amp could easily feed 10 sets of cans.