The easiest way and safest to thaw sewer lines is the use of a water Jetter with warm water NOT hot as you do not want to thermo shock the pipe
I unfreeze them with a propane blowtorch.
it is found in sewer pipes in the USA
Not normally even the connection to the public sewer is not covered
3" - 6"
With a wire brush.
No, it will destroy the pipe
Pipes. It is used for alot of underground storm, sewer or freshwater pipes by cities.
Probably not, but where does the water from the sink and shower go and what sewer problems are you having?
You could install your own sewer cam and get a look however doing so would likely involve getting in to your sewer pipes which is best left to a professional. Call a plumber to look in to your pipes if he can't find anything install the cam while he's got the pipes open.