I may have gone way astray here, so correct, please.
I-4-d. Quidam dixerunt aliquos vicisse Caesarem.
Quidam looks like the subject of dixerunt; hence: “Certain ones said. . .”
but both aliquos and Caesarem look accusative. So should it be Englished as:
“… Caesar defeated somebody”;
or, “somebody defeated Caesar”.
My intuitive preference, “Caesar defeated somebody.”
I-5-a. Homines quidam mirantur verenturque Caesarem.
Should it be “Certain men admire and fear Caesar”;
or, “Certain (men) admire men, and fear Caesar”.
It’s inherently ambiguous. (My favourite example of this is the story of Pyrrhus consulting an oracle and the oracle saying, “aio te Aeacida Romanos vincere posse” with the result that whatever happened the oracle could claim to have been correct.) Context would normally determine things but outside of any context I’d agree with your preference. Also, it’s technically “somebodies”.
I-5-a. Homines quidam mirantur verenturque Caesarem.
Should it be “Certain men admire and fear Caesar”;
or, “Certain (men) admire men, and fear Caesar”.