Hi!
If your workflow is creating rectangle annotations on the client, and converting them to redactions on the server using a 3rd party SDK, then no you will not need a PDFTron license, just a PDF.js Express one.
As a side note, the enableRedaction: true option will not work in Express.
Express does not ship with Typescript definitions so no we do not have an angular typescript sample. We do however have a simple angular sample.
Thanks!
Logan