No, the edict that allows you to work there increases corruption by one, just like re-opening the bar does. You can't be a receptionist at all, not even one who does her job perfectly, without increasing your Corruption. Which leaves... the gloryhole as the only side job that you can do on a non-corrupt run?
The edicts for more drink variety give more profits, and get Karryn drunk faster when she shares them. I usually keep a notepad window open to jot down the order in which people call and what they want, but that's because I'm crazy.
Her level of drunkenness affects her face, making her blush and such, but the most reliable way to tell is looking at the time cost for actions. There's a base value for when she's completely sober, and then 1-5 seconds added on to every action she takes based on how much booze is in her system at the time. It also makes her much more willing to flash people when they ask, instead of getting angry and refusing (slut level and boob desire are also factors)
The scene starts under two conditions: one is that she's at least a little bit drunk, and her desires and wetness level are high enough for her to be penetrated, which transitions directly into a sex scene (they dump out her mug and use it to collect semen). The second, much more difficult option (which unlocks a special title IIRC if you can do it ten times?) is to get her extremely drunk while keeping all her desires too low for a sex scene. This gives you a similar image with her bent over the table with a mug in front of her, but it's still full of beer, and she can keep racking up big tips as long as she keeps chugging the beer (but keeping your desires low in that position is... difficult, and if they get high enough for sex you shift back into the more common gangbang scene).
If you're going for that I recommend high level drinks, high mouth desire (when she kisses somebody with a drink in front of them they feed her some of it), and never fixing her clothes because if people can't ask her to flash and can't try to strip her further they're more likely to offer a drink of a kiss. It takes a really high Mind score to keep your non-mouth desires low enough though. You'll also want talk/sight resistance.