When a sentence begins with a parenthetical clause (uncommon, I'm sure), how should the following portion be capitalized? My thought is it would be either
(In my opinion, at least[,]) the play was terrible.
(In my opinion, at least[,]) The play was terrible.
Since "The play was terrible" is a complete sentence, and "In my opinion, at least" is a parenthetical attachment, should "the" be capitalized? Should a sentence even start with a parenthetical clause?
Additionally (I will remove this part from the question if it turns out to be too separate an issue), should the comma after "at least" be present? Were the sentence written to include the parenthetical statement, it would be included, but it seems very strange to me to end a parenthetical statement that way.