For starters, that's a lot of fish in a 10 gallon tank, so I wouldn't expect them to survive long. When healthy those fish grow very rapidly, and they now have no room for growth spurts.
Can you post your water params for ammonia, nitrite, nitrate, and pH please?? The first signs of trouble will likely show up there.
With that said, they will need a much larger tank asap, those fish get pretty decent size. The
Upside Down Catfish average about 4 inches, and the pictus average 5 - 7. The problem is that these fish are prone to stress, competing for food, and very prone to illness due to stress and poor water quality. All of these fish you have listed are scaleless fish, and the minute the water quality gets bad, they are prone to open sores and burning of the skin from ammonia and nitrites, or very high nitrates (over 40). Pictus are one of the harder cats to keep because of this reason, the upside down cats are a bit more sturdy.
At their current sizes they should be in at least 75 gallons to be able to find enough territory away from each other, and lots of decorations and enough caves to account for each fish. Please do not expect them to share cave territory, this is highly unlikely and usually turns into a fight for it instead. The fact that your upside down cats are already hiding is evidence of the lack of territory.
As for what to mix them with, that will depend on the size of the tank they end up in. If you're thinking of at least 125 gallons, yes, they could mix with bala sharks. I have seen them mixed with irridescent sharks, but that is not a fish I suggest to a beginner or anyone with a small pocketbook. Irridescent sharks top out around 3 - 4 ft, and are also very sensitive to water quality and stress. They are also known to be prone to injuries from smashing into the sides of tanks due to lack of needed space. They are very active and need a lot of length/area in the tank to be healthy. For just 1 you could expect to need about 900 gallons if you're planning to mix it with anything... 500+ just for the shark to find enough area.
Red tail sharks are going to be competition for territory and food, and are a lot more aggressive, so I wouldn't mix those in either. The common black sharks or black fin sharks are also not an option because they would need brackish water.
Please be aware that the fish you have currently will require softer water (pH of 6.5 - 7.0) and warm enough temperatures (78 - 80). Even without knowing your water parameters yet, if you're not doing daily water changes yet, you do need to. 20% every day without digging down into the gravel more than once or twice/wk. It would be a good idea to keep them on that water change schedule until you get them into a much larger tank where the waste levels will be more managable with just filtration and weekly water changes.
I hope this helps you, please ask if you have anymore questions. I am very familiar with both of these species of catfish, and their needs. There are other fish to consider mixing them with besides sharks, so once I know how large of a tank you're planning, I can give you more options.
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