Power BI basic doubts

Question 1: 

There are multiple ways to handle this. 

Here is one: 

Create a new table with only the topN results: 

Create a measure to count the times the name apprears in the first table: 

Changes the 'Value' settings to be 'Count' (rather than sum):

Final results (both tables side by side): 

The name Oscar does not appear on the second table, and count of each name is on the second table

Question 2: 

This is possible. 

For a basic design on how to achieve this, you should use a 'Dimensional' table to connect tables together (Model View shown below): 

These types of tables connect the data together and allow for calculation to be performed: 

Here is the measured used to do this: 

Here are the columns used to make the final visual: