By valid I mean will they stand up in court if challenged ?
If i precede my wife in death I wish to leave my estate to her, likewise she will leave her estate to me should she precede me. In the event we died together (car crash), would we need to do a joint will or should we stipulate our final wishes in our individual wills.
Since I do not practice in your state, I cannot give you a definitive answer to your question, however, to the best of my knowledge no state has approved videotaped "Wills" because they have to be prepared in a specific manner. That normally includes at least two witnesses to the signing of the Will and other specific ways of stating that the person is of sound and disposing mind. If there have been no cases litigated to this point that wound up approving videotaped Wills, then you and your wife would be taking a big step and relying upon a technique that may later be set aside, along with the Wills.
Its best to follow the presently accepted way of drafting and executing your Wills until your state allows for them.
On the other hand, it sounds like you may not require mutual Wills if your mutual intent is to give everything you have to your spouse and vice versa.
If you died in an auto accident together, your Wills would provide for alternate recipients of your estates as well as a determination of which of you is to be presumed to have died first.