お after お In what cases there would be written お rather than う after 'o'-ending kana (お,こ,そ etc.)?

か゜ symbol How is it pronounced? Is this a kana, or not? Does it have any meaning? In which cases it used?

ゐ and ゑ kanas In what cases they can be used and in what cannot?

What does サウ mean? None of the online dictionaries couldn't help meExamples: サウ云フコンディションニ成っテシマフ. サウ云フモノニ. サウ云フイベントヂミタ日ニハ. I also seen ヤウ instead of サウ in similar circumstances

Is there any significant difference between みな and みなさん?