Most insightful analysis I could find, but the lack of "funny" comments was disappointing. Have we all lost our senses of humor? The debate was certainly a target-rich environment for jokes.
I want to expand on one of your points and introduce one new one. The old point is whether it is "smart" to avoid paying taxes and the new one is branching from your broad attribution of "they're both liars" to consider the kinds of lies and liars.
Trump can claim that he didn't actually say he is not paying taxes, but he definitely claimed it is smart to not pay them. As a logical rule, "If 'smart', then 'not pay taxes'." You have surely heard the Donald claim he is smart. Modus ponens, he does not pay taxes. We also have an existence proof from the tax returns Hillary cited, but maybe Trump will claim he has become more stupid than he used to be. I'm not holding my breath waiting for that claim. (Then again, confessing to not paying taxes in front of 80 million tax-paying voters certainly could be regarded as evidence of stupidity.)
However, I reject the claim that not paying taxes is good. There are certain functions that can only be performed by governments, and if everyone followed Trump's example, then society would collapse. We can (and probably will) argue all day about what those functions are, but absolute nihilism loses as soon as two people agree to work together against the one nihilist.
Now onto the topic of liars and lies. Perhaps the easiest way to approach the topic is by considering it from the perspective of professional versus amateur? I would say that Hillary is a professional liar, AKA a lawyer. A large part of legal training is learning how to "handle" the truth when it conflicts with the best interests of your client. You hire a lawyer for that reason, and the main thing I dislike about Hillary is that her top personal identity is probably "lawyer" or even "corporate lawyer". (I certainly wish our top politicians had higher personal identities such as "philosopher" or "statesman", but that is not how it works in America these days. "Government of the corporations, by the lawyers, for the richest 0.1% shall rule the earth.")
In contrast, I would argue that Trump is an amateur liar. If he was just a real estate agent, then you could argue he is hired to lie convincingly on behalf of the actual property owners he is representing, but if he is an actual player in the game (as he claims), then he is just lying for his own advantage--and the thousands of lawsuits are evidence that he's pretty bad at it.
In conclusion, I think Hillary is a skilled lawyer, and if her client is the American people, then she will represent their interests skillfully. Indirect evidence, but I actually think she was a fairly effective Secretary of State who inherited an incredible mess from Dubya. President Obama was able to focus more on the domestic messes because she was doing so well with the foreign messes.
Getting a bit far off topic, but I think my ontology of lies is relevant (with apologies to Heinlein):
Level 0: Self-contradictions. You know there's a lie without checking (and it's possible both sides are false). Most of Trump's amateurish lies are L0. (He's a L0ser?)
Level 1: Counterfactual. Any fool can check the facts. Many of Trump's lies are L1.
Level 2: Partial truth. What makes it a lie is knowing the rest of the story and withholding it, but this can be a professional technique. This is where Hillary usually is. (She would doubtless claim that time constraints preclude full disclosure, but lawyers are also taught how to stall.)
Level 3: Framing. This broad category involves distorting the meanings of words or providing misleading contexts. Also logical tricks like the classic "Have you stopped beating your wife yet?" This is actually where serious propaganda works. Trump has no idea (unless he's clinging to his teleprompter), Hillary sometimes uses these techniques, but mostly Level 3 is for the serious professional liars like Roger Ailes. (BtW, when Ailes bails, then you know to dump Trump.)
Me? Tell a joke? Sorry, but as an original Trekkie and fan of Mr Spock, I had my sense of humor removed.