When you arrive at bkk look for domestic flights transfer. There is immigration desk where you get stamp into Thailand. Then you go to your gate for CR flight.
if you need more than 60 days then she can apply online for an E-Visa. Someone already post the link for it. And here is the step by step guide for the process
If she holding a German passport then she just enter Thailand with visa exemption 30 days and extend once at nearby immigration office for 30 days so that’s total of 60 days in Thailand.
Hoang is a common name. Try your name in FB search. You will find a lot of people with the same name. My father almost get denies entry at China for having a same name and birthday with another guy who on the watch list. Luckily that guys photo looks different.
As what Brandon said, you need to contact a lawyer.
As Steve said many insurance companies won’t cover you unless you are the owner of the bike. Travel insurance covers hospital bill. But you need to ask if they covers accidents cost by riding a bike. Then do they require you holds a license or permit.
Getting an IDP or Thai license is just for voiding pay fine when police stops you at a check point. For insurance purposes get a travel insurance which covers accidents riding a motorcycle. When you riding a rental bike there is a basic insurance coverage from Thai government but it does not offer much protection though.