@Anisqoyo I imagine that the $35 covers all of the costs associated with putting something like this together. There is a team that works on this throughout the year. There are some materials that are provided as well. It is quite a big undertaking.
I attended 2 years ago and can speak to some of your questions.
I don’t recall any ‘additional advising’ being provided, even at a cost. But, not certain on this one. Every student at Preview has a scheduled time to sit with the advisor to review incoming credits, plan for the first couple of semesters and then ultimately register for Fall.
There are always challenges with registering at UF, even when they are 2nd and 3rd year students. It is part of the charm of UF. 
You can expect that you will not be able to get all of the classes you want at Preview and will have to make some compromises. Once registration is open to all, the student can keep checking for open seats in the classes and sections they want and they may come available. There is also the Drop/Add period where seats may become available. Plan to be frustrated with this process throughout your years at UF, then you will not be surprised when it happens.
I am not sure whether Honors students get any priority at Preview, but they do during the other registration cycles. Students are assigned a day/time to register based on a few factors including the number of credit hours accumulated and honors status.
The other thing to keep in mind is that they open a certain number of seats for each class during each Preview session. So, there is no advantage to attend an earlier session and you are not penalized for attending a later session.