Career question ?

No it would not be more money for several reasons.  First you are hired and paid by job description, a certif outside that would be useless, second, one license trumps many cents, so being a RN would make holding a pharm tech cert useless as well, you wouldn’t be in the pharmacy, same for phlebotomy. You wouldn’t be working as a phlebotomist and an RN, as two separate jobs, scope of practice delineates responsibility,  as an RN you can draw blood but wouldn’t be doing it all the time. So, just focus on the RN.

According to me, if you have certification for both then it's good for knowledge and experience but at the same time you can do the work for both so I will suggest to do focus on the one. 

Where my wife works they pay you the rate for the job you are doing, they don't give you extra if you able to do another job, but not doing it.

Not likely more money.

The pay rate does go up if you have multiple certificates and degrees.