May use royalty free music licensed under Creative Commons: By Attribution 3.0 as part of a marketplace content release

I can’t afford a copyright lawyer at the moment so I’m coming to the answer hub.
I intend to release a free demo to the marketplace and in its current state it has royalty free music licensed under Creative Commons: By Attribution 3.0 as the background music.
I explained what I intended to use the music for via email to the original composer’s website and a representative replied without stating any objections. All I got was basically “when you give credit it should look like this…”
May the music stay in provided I supply the necessary credit to the original composer?
Since others would then be able to migrate and use the music asset would this become a legal issue?
I stated that this would be possible/ likely to happen in my email to the composer.
I would inform those who download the demo to give credit in the same manner prior to using the assets but is that enough or do I need to create my own music for the demo to avoid legal complications?

If I were to use the music in a similar manner (as background music) in a paid for release to the marketplace would there be any other legal/ copyright issues that would apply?

Another question as well, since these are now UASSETS and only available to subscribers does it violate the “You may not impose any effective technological measures on the Work that restrict the ability of a recipient of the Work from You to exercise the rights granted to that recipient under the terms of the License” section if the demo or release were made available somewhere else (like steam) as a regular game?

That license is not a Non-Compatible License under the UE EULA, so it’s ok to use in conjunction with a UE4 project.

Thank you very much!