Citations when mixing of factual evidence and interpretation in one sentence
Footnotes should be placed in connection to the material that they describe. There is literally no reason other than a style sheet that they can only be at the end of a sentence. If it belongs halfway through the sentence, before you begin interpretation, then put it there, where it makes the most logical sense.

Remember, your writing is what is paramount. Use the tools you have to make your arguments and narrative work, rather than the other way around.