Those are 2 nice looking fish I don't see a issue the 40b is 3ft so its not like it has a small foot print , the only difference between your 40 and my 90 besides gallons is mine is a foot longer and 9 inches taller and the width is identical to your 40 ,
I have basslets and dotty backs they'll do fine as theirs plenty of hiding spots,
good news finally got rid of my large goldfish and large pleco , now my 40B is vacant , waiting for me to empty and clean it so I can add my predators to it , this will give them lots more swimming room than my 37g bowfront , I'm stoked
glad the mean green is gone I know how annoying it is , I just added a algae scrubber to my sump , thinking about the green out break gave me the idea of rigging it up it's not pretty but it works , I got bored still needs a few modification as it sounds like a toilet running lol, but I do notice a big difference as my nitrates and phosphate seem to be more stable,