Hi Hellwitu. I’m Epic’s lawyer, so I can’t give you legal advice or interpret your obligations under third party licenses. But, I wanted to point you to some resources that may be helpful.
You can find the relevant licenses for the third party software in the “Engine/Source/ThirdParty/Licenses/” folder and/or in the relevant .tps file. Those licenses will specify your obligations with respect to the third party software.
A helpful site to understand common licenses is: https://tldrlegal.com/