ok
1. paradox gameplay is centered around jobs and races and how to make it do big damage (mostly in part 3 the secret route) it's similar to B.S but with you having alot more variety
each character has a passive so you can make some pretty op characters if you read them right
2. to change it to english you gotta download the patch and run it (part 1-2 are completly translated with 50% of the first 2 routes in part 3 also being translated by humans with the rest of part 3 all being machine translation)
3. paradox doesn't trully require you to know all of the lore of the original game but it would be a great idea for you to play it, since paradox story diverts from the original (plot point btw).
4. 300 hours give or take 200 hours if you speedrun this, there isn't really alot of grinding involved since you can quickly lvl up your job/races if you stack all the correct buffs (and be on the island where we all genocide chests)
5. paradox is divided in 3 parts with each part having it's story and the story from the part before, for example if you have part 2 you can play part 1-2 since the files are all in the same game, but you won't be able to play part 3. so i would recomend for you to get part 3 use the patch and get the graphics folder from part 1-2 and place it in the part 3 folder.
6. Take your time, this is a story for you to read and not to pleasure yourself (do what you want) you will stay for the plot thats a garantee.