Is a person's statement "I will give so-and-so such-and-such" or "I will donate such-and-such to so-and-so" – without informing them – considered a promise, and does this fall under the issue of the obligation to fulfill a promise, knowing that it is merely an expression of an intention to do good and no one has yet been promised?

The scholars have not explicitly addressed the issue of expressing an intention for doing good as a separate matter, but it appears to fall under the definition of a promise (wa'd). A promise is defined as "informing of the delivery of good in the future" or "an announcement by the one informing about performing a kindness in the future." It is not a condition for a promise that the one being promised knows about it or accepts it, because it is not a contract. This is what distinguishes it from a gift (hiba), which requires offer and acceptance. In conclusion, what was issued by the questioner is considered a promise.