We’d like to know if all versions of the AWS Provider are compatible with all versions of Terraform.
No. Terraform providers could require specific versions if they depend on newer features. One example of this is the major change between 0.11 & 0.12 meaning most providers now only work with more recent Terraform versions.
It is up to the specific providers to publish any requirements. In general it is advisable to use the most recent versions of Terraform & the providers you wish to use.