But you may want to research this seller's background, and whether they've been involved in any legal action in the past (either as a plaintiff or as a defendant). 

Is there some other action that others have found to have a good success rate?

I've been taking action in real estate since about June 2014.  

All available siblings would have to participate.Tthis is a process that gives all parties who may have interest in the property to make a claim within a certain time frame, if no claim is made by the missing sibling whoever filed the action will be awarded free and clear title..

Trucks that have the call to action on the back generate more calls as well because people sit there looking at the "sign" (back of the truck) in traffic.I've gotten more people to ask me about my business (e.g., standing in line at a store) when I wear a SHIRT or JACKET with the business name on it.  

If you get no action and you don't want to take the lesser price then pull it off the market and go for #3 then.

My partner has about 10 years experience in this field, so a lot of what I read and hear on BP and the podcasts I get to see in action.

Sometimes the deal and the numbers will determine the best course of action.

I would say that if you are looking on the market place on bigger pockets then try to stick to people who have a lot of posts and action on here, this way you might be able to get a sense of them and they would have a reputation to lose if they do you wrong. 

Later you can go back for the actionable specifics in your area of interest.