To Single Cat: about living trust

we plan to move to US based on job relocation. normally, after 2-3 yrs, we will get green cards then maybe we will apply for nationality. We plan to buy the property in US and put it under living trust and the beneficiaries will be the longer living partner and our future kids.

Questions are:
1. do we have to obtain green card first in order to use living trust?
2. what is the difference between green card holder and US citizen when
using living trust? I heard that if one of the partners die, then beneficiaries
will be charge a big % tax on trust fund if he is not US citizen.
3. Is it legal for the trust founders to exclude his kids from previous marriage
from the beneficiaries?
4. one chinese, one Dutch, 2 kids from his previous marriage Dutch, if there
is a debate on the trust beneficiaries later, which country law will apply,
US, Netherland or china? or everybody can go to court at any of these
location?
5. is that correct that goods under the living trust are out of court debate?
If the arragement of the living trust's beneficiaries has confliction with Dutch's inheritace law (kids are protected to get certain % of the inheritace even if they treat the parents as pigs)

THank you very much! I know it is complicated.