"The food and waste" cannot be picked up by a test. Ammonia can be. But what I'm saying is, without the exact readings, how do YOU know it's fine? What if the reading is 0.25, or 0.5, and the guy testing it considers that to be "fine"? You need 0. Without testing this for yourself, you still don't know what the reading is.
Is he charging you for these water readings? Some places do, some don't. I really think you'd be better off with your own kit, they're not expensive and pretty much essential in this situation.
As for how many fish would be acceptable, it depends on what you want to keep.
The biggest no-no on your list is the clown loach situation. Like already said, they need enormous tanks because they can reach a large size and need to be in groups of 6+. The fact they're currently small is irrelevant - in fact its arguably worse, as they could suffer irreversible damage from being stunted.
It's also far too small for seven angels.
'Spotted Catfish' and 'Green Algae Eater' worry me as these could be anything. Could you take a picture?
What is your maintenance routine now? How often are you doing gravel vacs and how much water are you changing weekly?
After reading your filter cleaning description, I think you're being a bit over zealous with that as well. Replace the fine poly filter each week but the sponges and any other media don't need cleaning that thoroughly every week, just give them a slight squeeze out in tank water every few weeks, just lightly rinse the worst of the gunk off the outside. I wonder if you're affecting the bacteria levels by being too thorough. Dont mess with your filter too much.
