There is no single deciding factor. It's weighing the State's evidence against your available defenses. The most important pieces of evidence in a DWI are the breath or blood score and the video(s). After you have reviewed all of the discovery with your attorney, you will be able to evaluate the DA's offer and decide whether accepting it outweighs the risk of going to trial.
Signing a 12.44 does not make a case aggravated. It is either aggravated by the facts of the case or it's not. A DWI Child is not aggravated for the purposes of sentencing. How this will impact his immigration status is a question for an immigration attorney.
These are all important questions you need to thoroughly discussed with the experienced DWI attorney you hire to represent you. (Your first deadline expires 15 days from arrest, so get on the phone!). Here are some nutshell answers:
Only your attorney, after thorough review of the state's evidence against you) can tell you the likelihood of dismissal in your case. .16 DWIs are not often dismissed.
The fact that you donated blood is relevant but does not negate your BAC.
Your attorney is in the best position to answer this question. Just because the return isn't showing on the system yet doesn't mean the witness hasn't been served. If you are unable to execute service, you may or may not be granted a continuance. It's at the judge's discretion.