I'm a MS SQL DB Developer looking to get more permissions on the server
I am wondering if Grant Control on Schema will cover everything I
need
Will Grant Control give me everything I need as a Database developer.

But you didn't write what exactly you need as database developer.
If you update your question with your tasks to accomplish, I'll answer on that. For now I can give you only general answer.
Having CONTROL on schema you have access to this schema objects only, i.e. you can

SELECT INSERT UPDATE DELETE and ALTER tables (but you cannot CREATE
new table because this requires CREATE TABLE permission)
ALTER and EXECUTE modules (but not CREATE new ones because you don't
have CREATE PROCEDURE/VIEW/FUNCTION permission)
GRANT permissions on your schema objects to user but not CREATE USER

You are still lacking SHOWPLAN permission having only CONTROL ON SCHEMA
and of course you continue to see only your own sessions using sp_who2
To see all the sessions on the server you need VIEW SERVER STATE server level permission.
To be able to see plans you need SHOWPLAN permission in all databases involved in your query (so if you use temp tables you cannot see the plan if you have no SHOWPLAN in tempdb)
To be able to create jobs you must be a member of SQLAgentOperatorRole
To be able to kill any session you need ALTER ANY CONNECTION server level permission.
To use stop button in SSMS you don't need any special permission

I'd like to know if I create an index and it is ever hit and how often

To be able to select from sys.dm_db_index_usage_stats you need VIEW SERVER STATE permission.
.............
It seems to me I touched all the actions mentioned in your question, if I miss smth please ask in a comment or update your question