In our case, Mr. Brown told my son during his interview that he is awarded the full scholarship then we receive the letter in about a week.
From what I learned, it does not automatically put you in Engineering Honors. But Mr. Brown can definitely help you to get in. One of the students in my son’s group did not apply to EH and Mr. Brown said he’s going to “fix the situation”.
You do need to apply UH separately, just like applying for EH. But I believe the deadline has past already.
As why do you want to do both, I’m not quite sure … according to many here on the forum, UH seems to have a lot of extra non-academic obligations. Maybe someone else can offer more insights regarding this?