Damn targets. They just add more confusion than solve problems 
So you mentioned that you want to deploy using CI/CD. That basically means that you don’t need multiple targets.
Just one target called development or local where you build your app.
Once you push your code to your bitbucket remote repo CI/CD takes the lead and deploys your stuff to AWS.
Wappler uses the dotenv package so if it finds at the root a .env file it will load the variables to process.env and that should be enough for your development environment/target.
Then you just need to make sure that your staging and production environments also load the env variables you want for each environment. Each hosting has its own way so make sure to read AWS docs on that.