Are there ingredients I should avoid in a brine?

The short answer is to just stick to salt, because nothing else is going to meaningfully impact the brining process. But there are certainly some things that would be actively harmful.

Your question and another answer correctly identify acids and alcohols as two of the biggest culprits. Common acids used in cooking include vinegar, any citrus fruit, yogurt, tomato, buttermilk, coffee, soy sauce (and many other fermented products), pop/soda and some teas. From your list, .

But you wouldn't want a very basic brine, either. It's less of a concern because there are so many more low-pH (acidic) foods and ingredients than high-pH (alkaline) ones—people tend not to enjoy the bitter taste and sometimes soapy mouthfeel of bases. Still, for the record, don't using baking soda in your brine unless you need it to neutralize the pH of a particularly acidic water source. (And even then, there may be a better solution; consult a water treatment professional.)

Baking powder, by the way, is a mix of base and acid (commonly baking soda and tartaric acid, but commercial products vary) that probably balances out as neutral-to-acidic when all's said and done. It has some applications in dry brining, and I've personally had success using a mixture of up to 1:4 baking powder to salt in a dry brine for a whole chicken. But the caveat here is that it didn't really improve the moistness of the meat at all, compared to pure salt; what it did was produce a crispier skin, and I've found it really difficult to get that crisping effect without also introducing some amount of bitter flavor, which is why I stopped using it. Personally, I don't think it's an improvement over the more traditional (?) method of rubbing fat between the skin and meat and/or basting. And if you're strictly interested in a wet brine (which I believe is implied when you say "5%") then I'd stay away from baking powder altogether.

Another thing I would avoid in overnight brines is any tenderizing enzyme such as bromelain, papain and ficin (found naturally in pineapples, papayas, and figs, respectively). In particular, products sold as "meat tenderizer" (whether enzyme-based or not) should probably not be applied for this length of time.

All that said, there's a much better approach in my opinion, which is to resist the urge to get fancy and just use salt! Table salt (sodium chloride) dissociates into very simple ions that transport far more easily through osmosis than the larger and more complex flavor compounds that you're looking to add to your brine. And even then, it takes many hours for those simple salt ions to fully penetrate your bird. Other compounds, like proteins and lipids and esters and all the various complicated molecules that we use to impart flavor to food, either can't or won't penetrate the meat in the time it takes for the sodium chloride to do its job.

I understand the temptation to do something extra-special by including aromatic herbs and spices, citrus rinds, etc. and look for a secret ingredient, and the brine that you create may itself smell heavenly—but I think Serious Eats puts it best:

For the time and effort it takes to make a flavored brine, heat it up, and let it cool completely, you're much better off making a flavorful rub or herb butter. You'll get just as much (if not more) flavor into the bird, use fewer ingredients, and save yourself some time in the process.

Honestly, I wouldn't add any of the ingredients you list to a brine. You may add a little flavor to the outside of the bird that way, or you may just be adding some nice smells to your kitchen the day before the meal; either way, my question is why do it in the brining step at all? You can just add these to your bird directly, using other techniques. I hear your concern about spices like star anise that you don't want to become overpowering (whole cloves also come to mind) and if you really want to put those in your brine, I can't think of any whole spice that would hurt the chicken—but I expect it would always be more efficient and effective to extract their flavors into a fat or alcohol beforehand, which you can then apply to the bird after the brining step. This gives you more options and, I think, a finer degree of control over your flavors since you can't exactly taste a bucketful of raw salty birdwater to see how things are going.

Of the ingredients you listed, there are approaches for all of them outside of brining. I'd tuck garlic, herbs, or herbed butters between the skin and the breast after brining and before the bird goes into the oven. The fat of the skin renders as it cooks, extracts the flavors from the "tuck in" ingredients, and bastes the meat. I'd rub sugar, dry spices, and spice mixes onto the skin before cooking (in moderation, so they don't create a thicker crust that will burn). If "onion" means a raw onion, the traditional approach is to halve it and put it in the cavity of the bird with a bouquet garni, or try half a lemon (instead, or in addition); and the sauces I would always save until the end. They work great in glazes (note that the glaze you plan on using already has soy sauce and alcohol as ingredients), for deglazing the roaster to make a quick brown gravy, or even as condiments in their own right (fish sauce, ooooh-mami!).

For all of these, a huge disadvantage of adding them via a wet brine is that the water of the brine will dilute them so much that you'll end up having to use a lot more of them to even have a chance at imparting the same amount of flavor.