Are there any issues with me choosing a local grocery store or
restaurant to conduct the transaction?
Yes. Strictly speaking, the interesting scenario you outline in the latter portion of this comment might render both parties liable to the store owner and/or others present (collectively, "the store") even if only one party causes harm. I will focus on this scenario. As for the store claiming ownership of the proceeds, I deem it unlikely to succeed.
Regardless of whether or not the transaction (and subsequent disturbance) can be considered a form of loitering, the store could prevail under principles of equity and hold both parties jointly and severally liable. That is because both parties deliberately arranged to utilize the store for an external transaction without the store's permission and which does not benefit the store.
Furthermore, the evident failure to notify the store in advance about the parties' plans implies that the store was deprived of the opportunity to assess the need for special arrangements, such as (1) ensuring that security personnel supervises the store during the meetup, or (2) conditioning that the transaction be performed at a more convenient time (or not at all).
To address the risk associated to sales through Craigslist/Facebook, Law Enforcement incentivates that these transactions be performed at police station parking lots and other places classified as "safe zones". This initiative makes sense because officers would be nearby and the place is videotaped in case a situation degenerates.