Is this a remodeling or addition to an existing home?

An addition

I'm not an expert, but for those beams that have a metal simpson bracket on them, I would think the other end of the beams should also have a simpson bracket. The key thing with those brackets is that they use the right number and size of nails.

I am not a contractor, but I built a deck last summer. I don't think our building inspector would have been happy with that, but I don't have experience with roof framing. And YES to the nails! Our neighbors also built a deck last summer, and they did not pass framing inspection until every joist hanger had 10 nails.

It isn't pretty, but your house isn't going to fall down. If the framer's got an inspection approval, you don't have much of a case.

If you're concerned, you could get a structural engineer to look at it. Did an engineer approve the plans? It would be best to have the engineer who approved the plans come take a look to confirm if it matches what's needed.

A structural engineer designed the roof plan. I’m more concerned with the execution of the plan than the plan itself

You have nothing to worry about; but next time you go out to eat, order dessert first.

To alleviate any concern, take millworkman's advice.

I don’t know anything about roofing but does this look odd? Or is it acceptable? I had a structural engineer look at my framing. He recommended some changes. If you are worried, it’s worth doing, even just for piece of mind.

Since you had a structural engineer design the roof, I would bring them out to verify whether what was built matches the plan. There are various areas that look like they might be on the field hacks to make things fit. Not sure if this is an issue or not, but I would pay for a couple hours of a structural engineer's time for peace of mind. In just the first pic, these are areas I would ask about. If there are metal simpson brackets on the top end of that brace, I would think you need them even more on the bottom end. But I am not an expert and your structural engineer is.

In my state, if an engineer designs a structure, he/she is required to inspect the work and sign an affidavit stating it was done according to the design drawings.