I'm worried about having too many fish and having too high of a bioload what do you guys think is an appropriate number?
This you will find a fairly helpful tool. Tells compatibility, water change suggestions etc.
Someone mentioned that Cory's have good personalities. If you keep that in mind when this site makes suggestions as to the compatibility of any two or more types of anything, you can see where that is a quirk which they don't factor in.
Of course when they say "NO/DON'T" and you say "yea, but it might"...it likely would be good if you had a place to move
the offending critter to, just in case they don't get along. Most shops will take back a fish they just sold you.
And when you said heavily planted, if one aria of that is a dense corner of stemmed plants which you have trimmed the top
off of so they fill the spaces in between each other from new sprouts coming up due to the trimming, the CPD will not stop
you from having a few new shrimp as the babies will stay in the dense aria till they get large enough to be out in the main
aria's of the tank. In fact, a sponge filter is all that's needed for a filter in there and if placed behind such a space, will
provide the babies a great food source as anyone who has a sponge filter will tell you that the RCS are always on it picking
food from it.