I see on page 77 in Gospel Principles this claim that "[stake patriarchs] are the word of the Lord personally to us". Is that just when they give priesthood blessings, or 24/7, including any jobs or political office they hold? Are they likely to abuse the trust of the people if they hold public office?

I had a Stake President who used to tell everyone he was the prophet for our Stake.

As far as I know patriarch is a higher calling in the Mormon Melchezidich Priesthood than apostle or prophet. But of course the bretheren find that threatening so they don't go around talking about it to the members.

Stake patriarchs are not prophets. When it was filled, the position of Patriarch to the Church was held by a descendant of the Smith line and he was sustained as a Prophet, Seer and Revelator.

Patriarch used to be a priesthood office between High Priest and Apostle. No I'm not sure since a stake president can now ordain a patriarch for their stake. Prior to that only an apostle or another patriarch could ordain one.

God's eternal unchanging priesthood was reorganized sometine in the 80s. Prior to that a 70 was an office between Elder and High Priest.

So hard to know anymore.