There were novels similar to Wanderers in the Heavens:
Book of Troubled Times, Author: Ji Cha
2:"Spiritual Realm Walker", Author: Xiao Langjun
3: The Tang's Table, Author: Jie and 2
4."King of Familiars", Author: Light Spring Flowing Sound
Fairy, Please Listen to My Explanation, Author: Mi Tian Building
National Forensic Medicine, Author: Zhiniao Village
7:"Wait, Heroine." Author: Guan Guan Gongzi
8: Mantang Colorful, Author: Weird Cousin
9:"Hidden Dead Corner", Author: Get Lost
Final Divine Duty, Author: Tuoba Goudan
Beyond Time, Author: Er Gen
This Game Is Too Real by Chen Xing LL
Red Heart Sky Patrol, Author: What's the Matter?
Ring of Destiny, Author: Squid Who Loves to Dive
National Master of Ming Dynasty, Author: West Lake Encountered Rain
Choose a Day to Ascend, Author: Otaku Pig
17:"Who's in Love After Rebirth?" Author: What's Wrong?
Deep Sea Ember, Author: Yuantong
Chapter 19: Cultivation in the Chaotic World of Demonic Martial Arts, Author: Wenplagiarism
20:"Who told him to cultivate!" Author: The Whitest Crow
The following is a detailed introduction of these novels:
1."Book of Troubled Times": Ji Cha's book, anyone who understands it will understand o(*^▽^*)o
2.<

One manga similar to Drifters could be Berserk. It has a dark and epic tone with complex characters and intense action.
In general, the Drifters anime is quite faithful to the manga. Some visual elements might be enhanced for the animation, but the core story remains the same. There are maybe a few new details added for better presentation, but they don't change the main storylines.
They are quite similar. The anime mostly sticks to the main plot and character developments from the manga.
It's quite similar. The raw manga and the adapted version share most of the key elements and storylines.
Yes, it is. The story has reached its conclusion.
Yes, it is. The final chapter was released, bringing the manga to a conclusion.
The main contrast lies in the nature of the content. The Drifters hentai comic goes into sexual themes that are absent in the regular Drifters series, which is more about action and character development. Also, the art style might be slightly different to accommodate the adult nature of the hentai version.
The 'the drifters girl' story is likely about a girl who has some connection to the Drifters. Maybe she's a fan, or perhaps she has a personal journey intertwined with the group in some way. Without more specific information, it's hard to say exactly.
I'm not sure exactly. Maybe there were some changes in the plot or publication schedule.
I'm not entirely sure as I haven't read it specifically. But generally, a novel about 'drifters' might be about people who are constantly on the move, perhaps exploring different places, cultures, or just living a nomadic lifestyle.