Did you tried the answer in above thread? Does it work for you?
I can provide more details for it, for example:
1) You can create a Toolset form for editing the CPT post, in this form display those extra fields.
2) After user created the new CPT post, redirect him to the new CPT post,
3) Use content template to design single CPT post
4) In this content template, display the Edit form link of step 1, see the document: https://toolset.com/documentation/getting-started-with-toolset/publish-content-from-the-front-end/forms-for-editing/
You can also use [wpv-conditional] shortcode to check if current user is the post author, and display the edit form, for example:
[wpv-conditional if="( '[wpv-current-user info="login"]' eq '[wpv-post-author format="meta" meta="user_login"]' ) "]
Display the edit form link here ...