Migrating *portion* of state from 0.11 to 0.15

How many resources are you talking about here? Frankly it might be easier to script importing all the existing resources than going thru each version if its for a small amount of things.

You can’t do anything with 0.11 except move to 0.12. To get to 0.15/1.0, you’ll have to again pass thru 0.13 then can go to 0.15… as long as there isn’t anything crazy/odd in your HCL.
It should be relatively quick to iterate thru the versions - so option 3 makes me think you tried this and it didnt work?

Have you seen GitHub - GoogleCloudPlatform/terraformer: CLI tool to generate terraform files from existing infrastructure (reverse Terraform). Infrastructure to Code ?