If after 16 months of marriage my wife and I have decided to divorce what, if anything, will she be entitled to?

You have a couple of options/ideas---so I'm just going to take them one at a time....
First, waivers are scary to most people who are representing themselves because it implies they are giving something up.... which they are... they are potentially waiving their right to be served or heard depending on how the waiver is worded.  If she is good with the decree that you have, then have her sign it and go to court with you to do the final "prove-up"-- which is a five minute hearing before the judge where you ask him to grant the divorce and approve your agreements.  Her appearance and representation will be sufficient proof that she has knowledge of the law suit.  Your second option is to ask her to file a general appearance and then sign the decree.   The general appearance is the same heading that is on your petition, except the title will say "General Answer" (instead of "Original Petition for Divorce."  After the that, type the sentence:  "I am the respondent in this case and hereby enter by general appearance."  She can then sign it and you can file it with the clerk.  Once she does this and signs the decree... then you can go get your divorce finalized.   My main message here is don't get hung up on the waiver.  Understand that some people are logically resistant... but you can still move forward with some relatively easy fixes/compromises.
Your second main issue is what could she get.  Texas does not use a 50/50 standard--- the standard is fair and equitable.  This may or may not be 50/50.  The judge can award her a portion of your 401K that accrued during the marriage-- but that does not mean he is required to.  If you lived apart for virtually the entire marriage-- and were basically "divorced in spirit" from the get-go, then the judge can take that into consideration and say "she keeps her stuff and you keep your stuff."   If there was bad conduct on either parties part that caused a financial strain on the other spouse, the judge can also take that into consideration when dividing the property.  So... the bottom line is that there is no guarantee what he will do... but the judge should do what is fair and equitable.  I'm sorry this part of my answer is a bit vague, but I would need more details to give you a more definite answer.  To know more about what your local judge would do... arrange for a free consult with a local attorney that routinely practices in front of your judge so that they can give you a better feel for his approaches to "fair and equitable."