I have limited experience but I think both of those sentences are correct...
"For many years" is how we say it in English I think. Literally translated I assume it would be "Romans many years war were waging" rather than "Romans for
many years war were waging"
The verb to persuade persuadeo often takes a dative, I think it is a dative indirect object. So generally, you can expect dominus (indirect object) to be in the dative (domino) if you see that verb.
Surely "are here" would only be used if there were crowds of men in the plural (turbae virorum).
A more experienced Latinist will probably have more to say.