Hallo and welcome to Charming! :D If you have any questions, feel free to reach out. I'm available via PM or Discord if you have it!
My first instinct for networking is to just throw everyone at everyone lmao but to start out with:
is the owner of Quality Quidditch Supplies in Hogsmeade so I imagine that she and Clarence might know each other! She's very friendly and is also an inventor so I feel like they'd get on quite well.
used to live in Hogsmeade as an artist and conservator. She likely visited the apothecary a lot for ingredients for mixing paints! Earlier this year she received a letter from a distant cousin who bequeathed a fortune that allowed her to move from Working Class to Middle Class; when she went to meet her cousin in Italy, she stayed for the summer for an art intensive. Upon returning to England in September, she was on one of the ships that got attacked by dragons, and has been at St. Mungos as a coma patient ever since. I have a bit of an abstract plot for her that could be interesting as well!
finally I have here whose family owns Evergardens, a magical greenhouse in London! If Clarence ever sources his materials from other places, the Apothecary and Evergardens could be an interesting business partnership, since Evergardens has a poison garden and helps supply the hospitals with herbs and such 
I have more, but those are some good connections to start out with. Feel free to take or leave whichever you'd like, I'm down for anything! ^_^
Hi Dani! Welcome to Charming!
I have some pretty good options for you! owns the sweetshop on High Street! He's pretty outgoing, easygoing and easy to get along with. I've always headcanoned that he knows most of the shop owners on High Street, having been there for a long while now.
is part of the prolific Potts family and they own the florist in Hogsmeade. Her mother runs the shop, her father Basil is a marine herbologist and a few of her sisters work in the shop! Daff owns her own florist in Diagon Alley now, but if there was a good working relationship, would do business with him as she has her own greenhouse etc!
is the herbology professor at Hogwarts, so is potentially connected via the plant supply route.
is the Hogsmeade Chief constable, close in age and in station, so they might also know one another!
is a local midwife who probably need supplies fairly often!
Your characters sound amazing! Messaging you both to set something up! Thanks so much! :D
Hi Dani! <3
I have a
ton of characters, but off the top of my head these are probably my best bets for plots!
was the year above at school and is head of Potion & Plant Poisoning at the Hogsmeade Hospital, so I imagine they know each other/have some kind of working relationship and shared potions-nerdery! Ari is also gay, but since his wife found out about his affair last year and he ended it he's been on a downward spiral and is quietly depressed and self-harming (general tw for threading with him atm!). So he's been taking small amounts of poisons and probably buys his ingredients from the apothecary, which Clarence could side eye.
was in the same schoolyear and formerly middle class – now she's a porn model and opium addict, lives a bohemian lifestyle and probably needs a sketchy potion every once in a while, lol.
is grumpy as hell but is a dragon-keeper, so they might be business acquaintances if Clarence wants to buy dragon-based ingredients from Avalon Glen.
is a vampire who moves between London/Hogsmeade/the vampire caverns in the Forbidden Forest and does some black market trading. He also hires people as "human bloodbanks" in exchange for cash/thrills/sexual favours/whatever.
was going to inherit half of Flourish & Blotts in London before his best friend married the woman he loved, so now he lives in Hogsmeade instead. He's slightly frenetic and probably is a liability to himself when it comes to card games/making bets lol, so I feel like they could be friends through that, and is "bi-in-denial" aka he'll have flings with men when he's drunk and then pretend it never happened. xD
was a Gryffindor, an upper class pureblood but adventurous and laidback and likes fun. He used to be an Auror and now specialises in disguise and concealment so might have need of potions sometimes.
is a troublemaker in Hogsmeade during the holidays, so I'm sure he's caused chaos in the apothecary before and will happily do so in future. xD
Clarence takes immense pride in his work, fulfilling any and all orders (for the right price) and is known to never ask questions if these requests are less than savoury. Discretion is the cornerstone of his business, though the same can't be said for his private life. He plays fast and loose with his lovers, and rumours of young men coming and going in the night persist, but these whispers are eclipsed by his unparalleled expertise in potion making which ensures that business remains strong.