1) The CITY, (together ) with its suburbs , HAS a population of over a million.
The city and its suburbs have.....
Committee > a group of person > collective pronoun> if you see it as a group , then use "singular", but if you see it as different persons in the group , then use "plural"
2) The committee (ARE/are) not able to agree among THEMSELVES
Example:
The committees IS not able to reach an agreement wthin ITSELF
The tour group (is / ARE) arguing among (itself / THEMSELVES about where to eat dinner. ( different tourists arguing)
The tour group IS to be blamed for what IT has done
Additional Details:
3) George STOOD up lest anyone (SEE) him lying there in his evening clothes.
Goerge stood up lest anyone should see him ...better