1. Yes. If it's clear that the context is about a prison sentence, there is no need to state it explicitly. 2. No. 'Strive for their rights' doesn't collocate. (Yes, I know there's a song with that name, but it still isn't a phrase that works). You strive for something which is an ultimate goal, such as 'greatness'. 'Fight for', 'assert', 'protect' or 'defend' are all verbs which collocate with 'rights'. Also, 'taxed for heavy rents' doesn't work. Taxes aren't the same as rents, 'for' is the wrong preposition, and 'heavy' doesn't collocate with 'rents'. You could rephrase this as '..whom the landlords charged high rents' or '..on whom the landlords imposed high rents.' 3. No. It should be 'experience', because this is an uncountable noun in this context. One's cumulative work experience is different from the countable version of the noun. The countable version refers to single event which a person has experienced, and can be plural - for example, 'I had many interesting experiences.' This is not the same meaning as 'work experience.'

1) This one really depends on the sentences that came before it. Was prison or legal punishment mentioned soon before or after it? It's a difficult question, my instinct is that it would sound slightly better with "in prison" after it. 2) Yes, it is perfect. 3) You don't not need the "s" after "experiences". It's difficult to articulate exactly why, but when talking about people's collective "work experience", I don't recall ever seeing "experience" used as a plural. Hopefully someone else can give a more thorough explanation on it. I can only say that as a native speaker it sounds wrong.