I suggest you read iso22004 which was issued to answer queries such as you mention and does so in excellent detail, for example -
7.8 Verification planning
The concepts of validation, verification and monitoring are often confused.
— Validation is an assessment prior to operation, the role of which is to demonstrate that individual (or a combination of) control measures are capable of achieving the intended level of control.
— Verification is an assessment carried out during and after the operation, the role of which is to demonstrate that the intended level of control has actually been achieved.
— Monitoring is a procedure to detect any failures in the control measure.
I would only comment that, although the above Validation statement is, in Principle, in agreement with Codex 2008, practical situations, ie a running process, may force Validation to sometimes "overlap" erification". Such "overlap" is sometimes categorized as within an initial "Validation" study. (Other non-iso HACCP treatments explicitly utilise terminologies like preliminary Validation/on-going Validation, etc, etc.)
PRPs tend to have different operational bases. Their individual Verifcations will tend to vary accordingly.
Generically, as stated in iso22004 above, they are essentially required to be shown as effective in Principle for Validation, and effective in Practice for Verification (my own interpretations ).
BUT ISO22000 does not currently require Validation of PRPs, only Verification.