This is probably one of those questions that are so easy it shouldn't be asked but:

Officer makes arrest for possession. At time of arrest money is seized. Forfeiture never filed. How do we return money to owners? Addresses given at time of arrest no longer good.

I assume they have bonded out and moved on their merry way. I usually have pretty good luck having the bondsman help me locate his clients.

We have excellent luck using our court collection department. They have multiple memberships allowing them to perform some very far-fetched searchs.

I'd hold off for a little while and give it to them when they come to court on their drug case. This, of course, assumes that you have enough to charge them and also that they show up when it comes time to have their day in court.

Did not find this issue in searching the site.

Auditor finds monies held by Sheriff from seizure. Problem 1 is forfeiture never filed.
Problem 2 is 30 days is well past.
Problem 3 nature of party makes it unlikely they will be found.

Question: If cannot locate, how long does notice need to be published before send to State?

If the money was seized, and it isn't currently being held as evidence, disposition would be governed by art. 18.17, CCP, rather than the Property Code's escheat provisions. See art. 18.17(j). Article 18.17 applies to personal property, but its scope includes money. See art. 18.17(h). If a county officer seized the money, the purchasing agent (if you have one) oversees disposition. Otherwise, it's the sheriff's job. Notice has to be mailed to the last known address of the owner by certified mail. If he/she doesn't claim it within 90 days, it goes into the county treasury.