This is a point that I frequently emphasize when coaching candidates: if you find out that your structure from the beginning has been missing an important element, it is not only ok, but ESSENTIAL to refer back to your structure and integrate the newly discovered aspect into it! Here it is best practice to actively moderate the process, i.e.,
"This is a very interesting finding, and I believe it critically impacts my basic structure. So if you allow me, I will take a moment to refine my approach and then walk you through how the new element relates to the rest of the structure.".
Because guess what - this is what happens basically every week during real consulting work! You constantly iterate and refine, so doing this in a clear and logical way during the case interview shows a very important skill.
Regarding the recommendation phase, I would not ask the questions on time at this stage. I would rather frame my recommendation as contingent on the time horizon. E.g.,
"If you are looking at a short to mid-term time frame (<18 months), the recommendation is [abc]. For a longer time horizon though, I would rather recommend [xyz]."