I agree with others that preparing the application yourself can be troublesome, not because others might see you as an easy target, but because the process is full of pitfalls that are easy to hit if you don't know what you're doing. Based on your questions, I think that is likely the case.
First, there's no way for anyone to give you any usable prediction regarding whether or not your registration will be allowed, absent some obvious obstacles (which I don't see at first glance). To get reasonable guidance, someone would have to do a TM search for you and review the specifics of your intended mark.
Second, of course you can say your mark is in use even though it isn't, provided you don't mind committing perjury (which may even be punishable by jail time) and likely losing your registration in the future. Facetiousness aside, no, you can't say a mark is in use when you know it really isn't.
Third, don't worry about actual classes. Just accurately describe the goods/services associated with your mark and the examiner will assign the proper class(es). If you fall into more classes than you pay for, you can delete classes or pay the additional filing fee later.
Really, if your mark is important to you, you should really consider finding a qualified TM attorney to handle it for you.