You can only file a default if you have proof of service, or if they accepted service in writing. I would call the clerk and make sure you have all the final paperwork completed or call an attorney for a free consultation to better ascertain your situation.
One thing I would do is call your local bar association for lawyers in your state and see what pro bono services they have. In most states attorneys are required to do a certain amount of free work. Good luck.
You have to be careful with this. The reason is if the property is considered marital she may be entitled to half the value and not the sale amount. The court may also think you are trying to defraud her.
You may be able to contact Utah Legal Services for some free legal help. They may be able to help and give you the case law you are looking for. I would also cite the rule that you have found on service.
Yes, you need to get this corrected. The length of a marriage effects other items such as alimony. You can send in a corrected Decree in order to fix the problem with a simple motion to correct the order. Good luck.
In Utah you can file a petition to save your marriage and try to go to counseling. However, in order to get him to sign the documents you are going to have to appear in front of a judge and seek performance.
When you say "online" I am sure you mean using the paperwork that is provided online. The problem with that is your soon to be ex-spouse would have to agree to the terms. I would try to get into mediation and get it settled. That way your attorney can provide a lot of value to you.
You need to file an objection to it be filed with the court. If it has already been filed with the court then you are going to have to file a 60(b) motion to have it set aside and ask to be represented by counsel. If you do not do these things you run the risk of the court entering the divorce decree as final.