yes, but you are limited to the size and power level of the bike you use for the test.
Yes! Please see all the requirements and procedures in the motorcycle manual (related link).
A trike is considered a motorcycle and requires a motorcycle endorsement on your driver's license.
No, you can get a 3 wheel vehicle endorsement. If you have a motorcycle endorsement, you can drive a trike but not the opposite.
You can take the motorycycle test even if you don't have motorcycle yet.
No.
you can take an official motorcycle drivers test at a residence that gives out the test or it could be possible that you could take an online official motorcycle drivers test.
Yes, you need to get it.
no
In the UK, yes.
There are no free ones.
Basically you can, only if the two astride wheels are up front. If the two wheels are in the back, then it becomes a trike and subject to motorcycle regulations.