Who is liabile to pay gst (under rcm) on gta services?

Dear Experts,

Q1. In case a GTA does NOT levy GST under forward charge, then who is liable to pay GST under reverse charge in below 2 cases:

i) Seller is REGISTERED

Buyer is Unregistered

Buyer pays freight

Who pays GST?   ________________

ii) Seller is Unregistered

    Seller pays freight

    Buyer is REGISTERED

    Who pays GST?   ________________

Q2. And now let's say the GTA is unregistered so no scope of forward charge. Will this change who pays GST in above 2 cases ?