Re: Nikkah naama...
To put things in perspective, nikahnaama (or marriage document) is a social contract as well as religious contract and a financial contract. You can put any thing there, as long as both parties agree and it is reasonable.
One thing about the question of just giving mehr *to the lady in case of divorce. You can pay *mehr whenever you both agree i.e. at the time of nikah, one week after nikah, one year after nikah, on-demand or in case of divorce - thats up to you guys. And, it is perfectly fine that you stipulate that all assets of the groom AND THE BRIDE, that were there BEFORE the marriage will not be part of joint assets upon divorce, BUT, assets/wealth created by one or the other WHILE BEING MARRIED, can not usually be exempted. Premise being that the guy is making all this money, because his wife at home is supporting him (or vice versa), therefore, they are both entitled to a share of this wealth. So pre-nuptial wealth can be secured, securing post-nuptial wealth can be dicey and if it turns into a messy divorce, courts usually take a dim view of the pre-nup attempts to protect post-nup wealth. You can try, of course.