Ditto those who say that "don't end a sentence with a preposition" is a rule that should be cheerfully ignored.
That said, if you are writing for a teacher or an editor who insists that you follow this rule, the conventional way to comply is to reword the sentence to say "for which", with "which" referring back to the appropriate word. In this case, " ... for all of which we would have to account". If that sentence seems awkward and harder to understand: exactly. That's why the "don't end a sentence with a preposition" rule is stupid. It forces us to make sentences that are more complex and harder to understand just to comply with an arbitrary rule.
In this case you could also do it by eliminating the passive, for example, "... and we would have to account for all of these." Or you could reword the sentence to not use a preposition, like "... and all of these would have to be considered" or "... and solutions would have to be found for all of these."
I've often had conversations, in grammar and in many other areas of life, where someone tells me that I should follow some rule, and when I ask why I should do this, they say, "But I just told you! Because it's the rule!" I ask, "But why is it a rule? What good does following this rule accomplish?" and they stare at me blankly like I'm insane, or say something like, "No, it really is the rule. See, it says so right here in this book." And they seem to honestly be unable to comprehend that the fact that somebody who called himself an expert wrote something in a book might somehow NOT be binding on all humanity for the rest of history. Of course if someone CAN give you a good reason for a rule, if they can point out how following this rules serves some good purpose, that's a different story.