Critique my answers and how would you have answered these UX interview questions?

A while back I had a interview for a UX designer position, I made it to the 2nd round where I was given an assessment to redesign a form then present it afterwards. The presentation went well but I stumbled quite a bit when questions were being asked.

1. Q: Which part of the design process would the developers would be involved? When would you handoff the completed mockup to the developers?
My process was as follows: [Empathize] --> [Define] --> [Ideate] --> [Prototype]
Empathize: competitive research, user research
Define: project scope, persona
Ideate: user flow
Prototype: sketching, high-fi mockup, interactive prototype

My answer was to involve development in the ideate and prototype phase since the ideate phase would give the developers an idea of the overall skeleton and structure of the product. During prototype phase would be where they would get a look of the mockups and be able to see if there are any concerns regarding the features involved. And if none, then we can hand off to development.

2. Q: The overall form is quite 'white,' would you introduce any new colors to the design?

My answer was that it would depend on what colors would be introduced since it should follow the brand guidelines to ensure consistency throughout the website. I think they were looking for something more cut and clear rather than 'it depends'?

3. Q: How would you design differently for users that aren't tech savvy?

I struggled the most with this question. I said something like..since it's a form, users may not be able to tell some items are checkboxes (being able to check multiple boxes), or if it's a drop down menu. We can also introduce more text / clear instructions into the design to give users an idea as to what that specific feature is looking for ie. you may check multiple boxes. What were interviewers looking for here?

4: Q: Since your proto persona is about a man named George who works at XXXX and is tech savvy, what about those customers who aren't tech savvy?

I also struggled with this question and said..Well since a proto persona is used to represent the majority of our target audience, we would have separate proto personas for the rest of the target audience. If say, we have 20%, 20%, 20% and 40% that represent our target audience then we would have 4 different proto personas. Or, if it was a 5%, 40% ,40% and 15% split, we would have two proto personas for the 40% audience. Honestly by this point I was confusing myself and just trying to give them an answer.

Anyways, just wanted to see how others would answer theses questions.