Soulsearchers and Company, scripted by Peter David. Originally published by Claypool Comics. According to the series listing at comics.org, #1 came out in 1993, and #82 (the final issue of the series) came out in 2007. That listing also indicates that many of the later issues did not include any clear statement regarding which company was now publishing it. I didn't know that, because I only have a trade paperback collection of the first six issues, plus a few single issues that go no higher than #12. Here's a cover-scan of that first TPB collection -- it may look familiar?
Note: A quick check through some of the individual issue listings on comics.org indicates that Richard Howell was often credited as "co-plotter" of the stories, which implies that he and David would usually hash out the idea for the next story together, and then David would script the actual dialogue.
Here are various points which correspond with your memory of what you're looking for:
Soulsearchers and Company was a black-and-white comic (not counting the colorful cover art).
The title reflected the name of a small business being run by some obscure superhero types who were just trying to make a living by investigating strange phenomena. Specifically, I've heard that the basic idea started as a pitch David made to Marvel, requesting permission to revive their "Defenders" team concept with a very humorous slant. In case you didn't know: In the 70s and 80s, the Defenders had a long-running title, and were sometimes called a "non-group" becauses of their rather disorganized nature. (In at least one storyline in the 1970s, it was asserted by a friend of theirs -- a film student who had prepared a piece about them which was run on televison -- that any costumed hero could simply choose to start calling himself a "Defender," and that would qualify him as a member, since they had never developed any formal written rules on the subject which required any other process for joining.)
The whole thing was meant to be funny -- the characters spent a lot of time bantering, and they sometimes encountered blatant parodies of other comic book concepts (such as characters from Neil Gaiman's Sandman.)
One of the regular cast members, who regarded himself as the brains of the operation, was a cranky businessman who -- before we ever met him -- had magically been transformed into a talking prairie dog, very much against his will, and didn't know how to get back to normal. (He is dangling from a carpet bag in the lower-right portion of the cover art shown above.) His name was Arnold Stanley, often addressed as "Mister Stanley." I believe he was the person financing the Soulsearchers operation as it began, and he hoped to make a good profit from it. I had not heard that writer Peter David ever explicitly asserted that Arnold Stanley was meant to represent David himself, but it may well be true!
One of the other regulars was Kelly Hollister, an "apprentice witch." (She's the blonde sitting on a guy's shoulders in the scanned image above.) As I recall from the stories I haven't read in ages, she was beautiful, cheerful, naive, and tender-hearted -- a very likeable person. I can't remember if she had any older relatives, such as an aunt, who were also witches -- but it wouldn't be very surprising if at least one story established that magical gifts ran in the family.
I can't swear to how the plots were structured after the first 12 issues or so, but it is true that in the early days of the series, the typical issue was a self-contained story.
All things considered, I feel confident that this is what you were remembering!
P.S. Searching for "Soulsearchers" and "David" on Amazon, I concluded that none of the stories are available for Kindle, but there are at least four "Soulsearchers and Company Omnibus" book editions which must reprint many of the original stories. (But I don't see any details regarding how many of the 82 issues have been reprinted this way.) Here's a link to the first Omnibus volume, alleged to be 298 pages long, but that page doesn't specify how many issues were included to bring it up to that length.