Regarding profiting off of specific samples from a sample library, it is VERY important to read the agreement from the publisher of the sample library. They are NOT all the same, so you need to read each one, when in doubt. Especially if you are selling sample libraries yourself, then it gets extremely important to know exactly what is allowed with your license. Remember, you have a license to use certain sounds a certain way. Read the license/terms.
Usually, but not always, it is very straightforward. Most library agreements usually allow you to use samples in the context of a music or sound design project, if it is mixed in with other elements, and it is not the primary or individual element, with no problems at all. After all, that is the most common use-case! There are variations of that, some nuances, but in general, for typical music production, itās pretty safe. There are edge cases though, so just read the license carefully.
And again, it can get murky if you are using a sample library to create another sample library, depending on what you are doing. Be very careful with this. For example, using a snare sample from one library, tweaking it a little, and reselling it as your own would NOT be allowed in MOST agreements. That should be obvious!
However, if you are producing a complex sound design element with heavy production and many layers mixed together, using a combination of samples, fx, processing, editing, etc., and then want resell that final composite element, then it might be just fine to do that. Again, read the licenses. Some licenses are VERY picky about what you can do, and they would not allow any kind of use for another sound library at all, unless it is specifically for music or in a larger production context.
Hereās the deal though, if you want to be 100% safe, then record your own raw SOURCE material yourself, then manipulate it, process it, mix it and layer it, slice and dice it however you want, and then you have your own product to sell. And Iām serious about that. Even on a very low budget this is possible to create some amazing original content with a handy portable field recorder like a Zoom or Tascam recorder. Then you take those samples and can work wonders with them with other tools, even in Cubase Elements.
Good luck!