Are GE referring to the use of syngas in the form of CSG/CBM...

Are GE referring to the use of syngas in the form of CSG/CBM when talking of calorific values?

Absolutely not. Syngas is not CSG/CBM, which is nearly 100% methane. Syngas is mostly hydrogen and carbon monoxide with minor methane and has a much lower CV. I think that Russian site might have been referring to "synthetic natural gas" which is highly methanated syngas, and which would have a CV similar to natural gas. It's also much, much more expensive to produce.

Does low CV impact on the ability for UCG to liquids?

Not really. UCG to liquids relies on the Fischer-Tropsch process. It is more important that the FT reaction is set up properly. That said, oxygen injection will probably produce a better quality syngas as feedstock for FT. At a higher price, of course. But then the end product is higher value too (diesel) so the extra money/energy is worth it.

CSG is a relatively wet gas, how does UCG compare?

I think your terminology is mixed up. CSG is what is called a very DRY gas, not wet, because it contains a higher fraction of methane than LNG and very little ethane or propane. The term doesn't really apply to UCG because syngas contains so little methane anyway.

Cheers,
Psi81