What you are talking about is counter rotating engines on a conventional wing mounted twin. The purpose is to eliminate a critical engine caused by "P" factor when both engines operate in the same direction. For this to function it is neccessary to use a normal prop on one side and a Pusher prop on the other. This cannot work simply by turning one prop around.

The engines must be reversed and some older two strokes that are front rotary valve can be reversed that have a rotatable front case plate and in other cases only a reversed timed crankshaft will work. This severly limits the avalible practical engines for any project. This is only a crutch and will not eliminate the need to understand how to fly a twin on one engine or the need for proper and immediate action when and engine fails.

Counter rotateing engines are what every new twin flyer will always get hung up on rather than finding someone who can teach the method to continue to maintain controlled flight on one engine without the old saw of "shut the other engine off and crash wherever you can." The neccessary actions with an engine out is not intuitive for a single engine pilot so its best to seek help and that is why I do considerable training on multi conversion and developed a special airplane for this training.

CR engines are not the norm with RC multis and while useful are not neccessary. One big additional problem is simply the unavaliblilty of a suitable selection of pusher props.

John