SQL Server order of execution and query plan
The order of execution you have quoted is a version of the Logical Processing Order of the SELECT statement - as the documentation states. The actual physical execution of the statement is determined by the query processor and the order may vary from this list. Also the SELECT node in the plan isn't an execution plan operator at all. This root node just labels the type of statement.

I.e., the DBMS is free to do it any way it wants, as long at it returns the same result as if it had used the logical execution order.