Hi,
All three translations are correct.
Do throideas agus do bhuas is Munster Irish. It uses a verbal particle do before the past tense of the synthetic form of the verb. This particle do was common enough once but is falling out of use. Outside Munster the particle is no longer used (except in verbs in the past tense beginning with a vowel - d'ól mé, I drank, for example. This Munster translation also uses a synthetic form of the verb. Information about the person is contained in the verb ending, instead of using a pronoun to indicate person, so do throideas = throid mé.
You will still hear these synthetic forms with or without the particle do, mostly from speakers from Munster Irish, and occasionally you will hear the synthetic form without the particle do from speakers outside Munster.
Outside Munster, the translation would be throid mé.
So do throideas = throideas = throid mé.
I'm no expert on Munster Irish, so how common the do throideas and throideas translations would be in today's spoken language, I can't say.
All of above also applies to verb buaigh, win.
do bhuas = bhuas = bhuaigh mé
Personally, I'd use throid mé agus bhuaigh mé.
With regards to capitalization, same rules as English. Only first letter of first word of sentence should be capitalized. The m in mé is not capitalised.