Most of the contracted writers wrote at home, but there were also some writers who worked in the company. This mainly depended on the company's requirements and the writer's personal situation. If the company requires the writer to work at the company, the writer may accept writing assignments at the company and continue writing at home. In addition, some writers might use the company's office equipment such as computers and printer to facilitate their writing work. Generally speaking, it was more common for contracted writers to write at home or work in the company.
It's hard to give a straightforward yes or no. Comic Concepts has its pros and cons. Some of their products are great, but there have been issues with delivery and customer support in some cases.
It depends on a few factors. If the animation follows the original story closely, uses good quality graphics, and has a coherent plot, it could be considered legit. But if it strays too far or has poor production values, it might not be.
Well, the legitimacy of G Mart Comics is a bit of a mixed bag. Some customers swear by it, but others have run into various troubles when dealing with them.
Honestly, I don't know. You could look into its reputation in the manga community, or maybe see if there are any reports of scams or issues associated with it to determine if it's a trustworthy store.