You only need "Create" or "Enable", and while it it possble, I have never used a toolbox tool
to create a database user or role.
It is unwise to use an insecure password for any user, much less the SDE user.
If you push the "Help" tab to the left of "Forums" above, then search on "arcsde postgresql",
the first few results will place you in the middle of the relevant documentation. Alternatively,
you can drill down through Geodata to Administration to PostgreSQL.
- V