The brown dots are most likely diatoms and normal for new set-ups and should resolve on there own after several weeks, they should be easy to wipe off and vacuum out with water changes until then..also-old light bulbs can cause this too-especially if they are over 1yr old
Ghost shrimp is a good choice-I don't remember off hand which of the ghost shrimp that can reproduce in a fresh water tank...give me a day or two and I will find out...but you need at least 1 female and 1 male and be aware that not only the Betta eating the shrimpletts but the ghost shrimp themselves will eat them...but having a nice mass of java moss can help...you may have to remind me later to get that information for you...gotta go for now.....
ok i wont put any more fish in how about 2 or 3 ghost shrimp? how many does it take to start a cloneney? by the way white clouds are fish that can live in fresh and coldwater i think the proper word is temeprmante?
Okay.....4-5g....IMO-I wouldn't add any fish...but maybe 3 dwarf cory cats...but that could be risky in 4-5g and they really do better in groups of 6 or more
Maybe 3 otto, once the tank has matured some in about 4-5 months-they would work
snails, different shrimp like red cherry or the yellows
Not a lot of swimming room and with limited swimming room come stress and more chances of the Betta catching them even with hiding places and plants...check into kuli loaches-I know they need to be in groups, I have never kept them but they are small and burrow I think....