Actually, this is a 2 part question.
Is it possible to use some sort of functionality to search through every stored procedure for a string and possibly rep
You can search the text of the stored procedure definitions using this
SELECT
Name
FROM
sys.procedures
WHERE
OBJECT_DEFINITION(OBJECT_ID) LIKE '%YourSearchText%'
Replacing is generally a bad idea, since you don't know the context of the text you'll find in the stored procedures. It probably is possible though via Powershell scripting.
I prefer this solution to any others, since I'm comfortable writing queries- so finding text in all stored procs, that are in schema (x) and database (y) and names that start with (z) is quite an easy and intuitive query.