It seems you have gotten over half-way there by understanding some of the possible legal issues, and realizing that you have to engage an attorney. Apparently you want to sell a product where aspects of the design of the product might infringe someone's copyright, and you want to market the product online. By providing samples of your product and the "other" products, you would provide a basis for a legal professional to assess the probability of an infringement lawsuit (how similar are the items?). You have some reason to think this might be okay under fair use (suggesting a US business, since there is no "fair use" in England), so a statement of your rationale would be useful (mentioning the 4 factors).
Similarly, be prepared to explain why you think that online marketing might have bearing on the question of infringement. I suppose the reasoning is that it's more likely that you would get caught if the product is marketed online, compared to sold by word of mouth with the aid of signs in front of your house.
You could ask "would disclaimers on the product help avoid an infringement lawsuit?", though since I can’t imagine how a disclaimer on a product would immunize against a lawsuit, you might be better off explaining what you would be disclaiming, and why you think that is relevant to the question of infringement.
Anytime someone intends to infringe copyright, the first question would (or should) be, why not get permission to copy the content in question?
You can Google "attorney referral service", which will give you the names of services, such as nolo, findlaw, lawyers, avvo, also the local bar association (sometimes) then you can fill in zip code, general legal area and a "what's the issue" summary, and you may get instant replies or eventual replies. This will tell you the names of some attorneys who purport to work in IP law as opposed to tax law or criminal law.