In git, you can merge multiple sources at once - a merge does not always have to have 2 parents. If you want to merge 3 feature branches into your current branch you can use
git merge feature-1 feature-2 feature-3
DSLite is basically a IPv6->4 tunnel that uses the same IPv4 Endpoint for multiple Clients thus allows a service provider to serve more Clients than they have IPv4 Adresses for
Because of this direct access to a router (or a port forward) via the IPv4 Address of a connection is not possible as there essentially is another router doing NAT in front of your router at home.
SSH multihop can be used to connect to a IPv6-only connection if the current connection only supports IPv4. It is however important to note that this will relay all traffic via the server used as a hopping point.