But you’re going to get an anonymous tip. After you get the info from the wiretap the phone is going to ring and a voice is going to tell you all the information you need. Poof. Not lying to anyone. Doesn’t matter that it might be another investigator that made the call. I agree that this is extremely sophomoric but I’ve seen it done. And the first scenario in the OP didn’t need a warrant to establish surveillance. Maybe just an excuse as to why they set it up.
Another way is to take some of the information and plant some seeds into one of your more reliable finks. They sniff around a bit and even if they come back empty they’ll invariably repeat what you told them. Except you told them that you heard it somewhere else and now you’re hearing it from them and they are confirming it. Most stains are on the hook for something or other and want to make you happy. There’s your informant to get a warrant. Can you believe this horseshit actually works?