Lincense question for commercial app

[Karl Berry]

    xelatex (which is according to CTAN licensed under X11 license) 

The XeTeX sources are X11. Its binaries are linked with kpathsea which
is LGPL. But this doesn't matter when you are just executing it in the
normal way.

    TexLive itself is not under GPL. 

There's no such thing as "TeX Live itself", apart from the
infrastructure scripts (tlmgr, install-tl, and so on; those are under
the GPL, but are irrelevant to the question of executing a tex binary).

TL is essentially an assembly of many disparate packages under
disparate licenses.

    Only some packages (based on CTAN search might be, or might be under
    another license for that matter). 

Each package has its own license, yes. Sometimes more than one.

You already read the TL license statement, but I'll repeat it

 [...] to the best of our knowledge, all the software in TeX Live
 meets the requirements of the Free Software Foundation's definition of
 free software, and the Debian Free Software Guidelines.

That's about the only general statement that can be made. --best, karl.