I like your approach of measuring temperatures and making charts and reports but here our actions are based mostly on experience. It's not hard to say whether carp or pike would live in such pond (most of lake fish would live there without problems). Temperature measurements can be useful when sensitive fish like trout. It might be useful to predict when fish would spawn.
But even if you know possible temperature range in pond, you can't be sure about future. What if summer comes hot as hell?
About carp spawning. Latvia is a bit too cold for them and in wildlife they spawn only in several lakes where they can find a shallow places with warm water and lots of plants. But it's possible to stimulate their spawning in this pond by raising water level and flooding a part of meadow. They like such places
Seems like our wels catfish is much bigger that your blue catfish. As I looked in Wikipedia, world record for that fish is 130 lbs. It's about 60 kg only. I have heard rumours about wels weighing more than 100 kg. Anyway this fish can't be really used as succesful fish capacity controller in such small pond.
I can't say that we don't have other predators here. Lets think...
Pike;
Eel;
Chub;
Ide;
Burbot;
Perch;
Zander;
Asp;
Rainbow trout.
I didn't mention salmon, sea trout, brown trout, grayling and some more that wouldn't live in a pond like this.
So, there is a list to choose from. Of course, not all of them can be obtained easily. I haven't heard about any fish farm that could offer ide, chub or asp. Probably the only way to get these is by usual fishing rod (it's not prohibited to transport fish to your pond. Just don't release them to other lake in wildlife). Never heard about largemouth basses here but even if I wanted some, I wouldn't be able to get them...
Once I thought about same sex pikes as the only suitable solution but I have to learn a bit about their gender differences. Imagine a little mistake and full pond of small pikes
Otters are protected by law but I hope that this law will be changed soon. Even hunters admit that their capacity allows them to be taken out of endangered animal list. But anyway I don't care about these stupid laws and at least 2 otters have been killed with traps during some last years. Traps are the only way to get rid of them - I have never seen an otter near the pond. They are careful.... You can't shoot animal that you don't see
