Exactly,
1. The CIA and IRS would still exist as Congress would still fund them and any Paul veto would be over ridden.
2. If Paul refused to enforce the law for example to pay social security or collect taxes, he would be impeached and removed as he should be.
The IRS is part of the Department of the Treasury, which is an executive department. They can be created or abolished at the will of the President. I'm really not sure where the CIA falls into the scheme of things, but I'm fairly certain that it is an executive agency, also.
If Paul refused to enforce the law for example to pay social security or collect taxes, he would be impeached and removed as he should be.
Maybe, maybe not. If Paul really were elected, it would be a pretty clear mandate. I'm not sure that it would necessarily want to tinker unless Paul's approval ratings were very low.