Hi, paul123, sounds like a lovely tank and community
But, speaking as One Who Knows Nothing, lol, I believe the adult size of the fish must be taken into account when adding stock, and that the larger (and messier) the fish, the more room must be allowed.
Have you calculated the total adult size of all the fish you're planning to add (don't know what 'heaps more discusses' adds up to, but implies many) to the 50 gallon, and made allowances for the actual bulk involved, rather than merely the total inches?
While I'm sure you have excellent filtration, it would be heartbreaking to set up a tank just the way you dreamed, only to eventually wind up with lowered immune systems/disease susceptibility or stress/injuries due to lack of individual space causing issues which might result in fish loss.
And with any luck, a real expert will come along any time now to give us the benefit of his/her knowledge and experience.
Because I so often talk through my hat that the brim gets soggy...