The scooter requires a very mature tank so that it can eat pods
, some might eat frozen food from the start but most are like mandarins, they only eat pods
. The butterfly will also give you eating issues, they can be super finicky and dont do very well usually.
The tangs are good, the blue can be a challenge too but 2 tangs in a 6 foot tank is good, you could even add a third tang if your heart desires in my opinion. I kept a blue, yellow and tomini in my 125g for several years and they got fat and happy.