Does D Gray Man Hallow closely follow the manga?

It follows pretty closely. There are only a few minor differences that don't really change the main plot or character development.

It depends. Some parts are very similar, but there are a few differences here and there.

Yes, it does. The Chainsaw Man anime mostly adheres to the manga plot with only a few minor changes that don't significantly impact the story.

Overall, One Punch Man follows the manga quite closely. There are some minor differences for better animation adaptation and pacing, but the core story and characters remain intact.

The Chainsaw Man anime mostly follows the manga, but there are some small differences that don't change the core of the story.

In general, the Chainsaw Man anime is a faithful adaptation of the manga. There might be some minor tweaks for animation and pacing, but the core story and characters remain intact.

One idea could be to have characters from 'D Gray - Man' interact with characters from another series in a post - apocalyptic setting. For example, they could team up to fight against a new type of Akuma that has emerged due to the crossover's unique circumstances.

Yes, it does. The anime mostly adheres to the manga's plot and characters.

Season 2 of One Punch Man does follow the manga to a certain extent, but there are some differences.

Yes, it does for the most part. The anime captures the key elements and plotlines from the manga quite accurately.