At a colo or location of you own you might hire two upstreams like CenturyLink and GTT, and since your (purchased) addresses would be reachable via either you would need to announce via BGP which requires an ASN. At AWS the only provider is AWS and are typically single addresses (even if you special requested 256 you might not receive a /24), further I don't know that AWS will issue an LOA to allow to you to announce their space via other providers.
An HE IPv6 tunnel is as permanent as you like, but they reserve the right to phase out the terminal you are using which sometimes means your prefix would change, and they expire unused tunnels periodically. IPv6 has builtin handling of prefix changes though it does not deal with related DNS updates, which you'd have to arrange.
An HE IPv6 assignment is from their allocation so you'd call that PA not PI, i.e., you can't take them elsewhere. To get addresses of your own you would need to apply to an LIR or RIR for an allocation -- generally easy to get a /48 without any/much documentation with a /40 generally requiring documentation but that's not free (250/yr for an ARIN allocation).
An HE IPv6 tunnel is as permanent as you like, but they reserve the right to phase out the terminal you are using which sometimes means your prefix would change, and they expire unused tunnels periodically. IPv6 has builtin handling of prefix changes though it does not deal with related DNS updates, which you'd have to arrange.
An HE IPv6 assignment is from their allocation so you'd call that PA not PI, i.e., you can't take them elsewhere. To get addresses of your own you would need to apply to an LIR or RIR for an allocation -- generally easy to get a /48 without any/much documentation with a /40 generally requiring documentation but that's not free (250/yr for an ARIN allocation).