I did not know that there were versions of Battleship that did not forbid placing boats adjacently. Of course, my remark about the extra information is only for the versions that do forbid it.
Regarding the oracle example: I agree with that, but I do not think it matters. You need to discover A and B. If A is more difficult, it is likely that you will ask the oracle for A. However, if there is no such oracle and (1) knowing B helps finding A more than knowing A helps finding B, it is better to search for B first. Of course, (1) is only true for the versions that forbid adjacency of boats.