Start a sentence with seditious?

The noun sentence (a text form, or a prison term) requires an adjective or article (a, the). But you can use it as an adjective itself, or as an imperative of the verb to sentence, to announce a...

Sometimes. BUT it depends on the sentence you had in mind. Very rarely the sentence works with but as the starting word.

For an answer to a question. "What time do we have to go to bed?" "WHEN the clock has the numbers 9,0,0." When as a question word: When did you live in Australia? When as a conjunction: We were...

According to the Chicago Manual of Style, 16th edition, it's perfectly fine to begin a sentence with 'and' or 'but.'

Yes. for example With referance to the request by......................