If you want to train the staff to feed, use the weekly pill containers. Fill the little sections with the daily amount of food then hide the rest of the food. You may have an easier time getting the resident to feed the fish correctly if she is functioning high enough to take her own meds.
This is exactly what I was going to say. Also, rather then shrimp, since you have the Betta, try Apple or Mystery snails. They are available in many colors - I got my pink and purple snails from Dakotagirl on this site. They are a beautiful addition to the tank and easy to care for. They are also a lot of fun to watch, and can be fed common foods like green beans, lettuce, peas, etc. They could be cleaning up the tank during the week, and on the weekends when you are there you can feed them extra foods to help with their health and growth.
As far as the other lady goes, I don't know what to say there. I have my Betta alone in a 2g tank with a small piece of driftwood and a fake plant. With the heater and filter, I think it's too small and may upgrade him to something larger. I can't imagine cramming anything else in there, my mental image of what you are describing leads me to think there isn't room at all to swim, do the fish just run into stuff or what?