With the size of the pangasious they do often kind of get stunted at somewhere between 9 inches and 30 inches they do grow massive even in captivity, they just get a snubbed nose from bashing into the glass as they are a migratory fish that swarm in huge rivers across Asia and really should not be kept in tanks but it happens they are in the trade in mass numbers but so few places that can look after them properly. If you can find somewhere that can take them I would get rid of them because they are just a nightmare you do not need.
The Knives again are big and they do grow to the big sizes, it does take time but they will get there and at the end of the day you get a fish to house it for life and with big fish like these your looking at 10 years +
The problem with the fish you have you have very few that you can hold for life in a tank like this as simply put these fish need ponds.
Also the Black/African Knives - you should not rehome just 2 as they can be kept as a group though in a tank it is not healthy how ever as a pair one will become dominant and harrass and even kill the weaker one.
Of the fish you have from the original list I would keep
1 Black Knife Fish (are these African Brown Knives or Black Ghost Knivefish?)
1 Fire Eel
4 Clown Loaches (though as I said you need to consider when is right to rehome them but to be honest given how many are available this size tank is a good home for them right now)
5 Red Tailed Botia (though I have heard these can be aggressive when adult and can cause issues to each other and other species, I would be worried about your Clown Loaches)
Then its upto you as what to keep in there, we have the same size tank and my rule is generally not to have anything that grows over 10 inches - though things like plecs and less active fish I would be more flexable. This is my thread with some pics of the tank and the fish - dont know if it will give you some ideas
http

/www.fishforums.net/index.php?/topic/374188-my-tank/
If I am being honest the fish you have are all less than ideal as a lot of them are large growing which the the tank though large just can not cope with. There are so many options with a tank this size and few of the fish you have now are the right ones.
Wills