I'm looking into possibility of using Drupal as a framework for web application that will access DB2 databases.

Considerations:
1) Use Drupal for user access and security (via LDAP).
2) Write various modules to perform CRUD activities on iSeries/DB2 via ADODB5/ODBC.
3) Use Single Page Application/Modules to perform various functions.

What I've done so far:
I have installed Drupal and created a test module that performs a simple select query from a table. The module includes ADODB5 which is configured to connect to DB2 via ODBC. I can move data to/from the iSeries.

What I would like to do:
1) Build a single page application via modules for each application. The modules will only be available on X page.
2) Restrict menu/pages/modules only to those roles that have access to them (they either get access or they don't). Example: Accounting should only see those applications/modules that are assigned to that role.

Questions:
1) Does Drupal sound like it will be a good fit? If not, it looks like I will be writing my own framework :(
2) If so, is the single page applications/modules a good direction to head?