UI customize

Is there a way to make the health bars bigger/larger?
Is there a way to make the unit info panel remain visible when a unit is selected but the mouse cursor is not over it?

I don't know exactly about your first question.
For the second question, I think there is an option in the in-game menu to display unit-stats. Have a look at the Ui & Interface menus.

I think I saw some console commands to adjust the size of the health bar

I tried these commands but they didnt work:

And for the unit info panel i couldnt find it in the options menu