Grant issues

I have an automated application that creates and updates tables in a database
and I have a "readonly" group containing all the users who should be allowed
to query the data. I am now a bit stuck. Can I:

1. Grant to users in the readonly group permission to do unrestricted queries
on the database (I know I can give this permission on a table but the
application creates tables as needed and I just want to give blanket
read-only rights to the users who need to query the data)?

2. Grant permission to create/alter views and temporary tables but not to
create nor alter functions, triggers, rules, indexes, etc. in the database.

I'm setting up this database on 7.3. Will schemas be of any use here (ie. can
I set up read-only rights on the schema that the application uses but set up
users with their own schemas where they can do whatever they want)?

Cheers,
Steve