1) Romans had many gods and godesses.
Romanis erant multus deus et deae.
2) Ab antiquis temporibus hominum generi universo agri cultura magnam utilitatem semper praebebat.
From ancient times whole humankind often had great benefits from agriculture.
Romanis erant multI dI et deae
Adjectives correspond in number and case, when modifying more than one gender of words, they take the masculine gender.
Deus has the irregular plural DI.
In your second translation, I believe agriculture should be the subject of the verb rather than humankind:
Ab antiquis temporibus hominum generi universo agri cultura magnam utilitatem semper praebebat.
From antique times (to) humans’ race (as a) whole acre’s culture great ultility always offered.
(From antique times agriculture always offered great utility to the whole race of humans.)
Yes, I agree, I made error in speed posting.
I agree that agriculture is the subject and you have translated literally as it is, but I didn’t liked the sound of it and I have modified it in a way I think that is more commonly spoked.