I wouldn't recommend keeping the giant gourami with any of the fish you have in Tank 2. Many of your other fish will likely get eaten by the gourami. Also, some of the fish currently housed together in Tank 2 are not actually compatible long-term.
Koi should not be kept at tropical temperatures. Keeping them at temperatures warm enough for all the other fish in that tank speeds up their metabolism, strains their system, and dramatically decreases their life expectancy.
Your silver sharks will likely get large enough to be a threat to many of the other fish in that tank.
Your pleco may eventually start trying to eat the slime coat off of other fish in the tank. This will leave them prone to infection and disease.
The giant gourami may eventually exceed two feet in length and need a huge tank even if it is kept alone. Any other fish in the tank would have to be large enough not to be eaten and either robust/armoured enough or agile enough not to be injured by the gourami. And adding more large fish may mean increasing the required tank dimensions even more! For a large full-grown specimen, you'll already be looking at a tank with dimensions of approximately 6'x2'x2' (or ~180 US gallons)!
You may be able to get away with a more modestly sized tank (of 100 or 125 gallons) if your particular gourami only grows to the 18" that seems to be more typical for captive specimens, but there's no guarantee that will be the case.
The pleco (if it's a "common" pleco) also has the potential to reach 18-24" in length. As does the koi. The sharks will likely be in the range of 12-14" when full-grown.
You'd actually be best off having three or four separate tanks for all the fish you have listed. If that is not practical for you at this time, it might be best to look into re-homing some of the fish. There may be another fish enthusiast in your area who would be thrilled to adopt some of yours or there may be a pet store that would be willing to take them on.