Sharing current - is that really more of a concern where LEDs with different characteristics are used? I have 8 digits with 7 segments each made of 3 parallel LEDs & decimal points made of 2 parallel LEDs being driven by a MAX7221, multiplexing at 800 Hz (not user changeable). Some digits use Red LEDs, some digits use yellow LEDs, some digits use Orange LEDs. I have been testing with this setup for a while, letting it run for hours at a time, and I am not seeing any visual difference in intensity anywhere.
I also have some really bright (10,000)mCD capable white LEDs paired up in parallel, driven by a 7406, that are not turned on anyhwere nearly as often as the digits, that seem to be doing okay.
I'll have to break open a couple of lines and stick a really low value resister in, measure the voltage across it on a scope and see what current they're actually running at.