Can I recite ziyarat ashura in English and do I have to recite the Salam and lanat 100 times and do I have to do sujood for the last part or are they all recommend bits?

Yes you are allowed to do all what you have asked. Its better to recite in Arabic ( at least transliteration) instead of translation. Also if you have time and courage better to recite Salam and Curse 100 times also better to recite ( Alla human lakal hamdu hamdash shakerina ala…) while you are in sajdah.