Incremental Refresh and data models

Hello Everyone

Would really appreciate help on this . I am new to Power BI and a bit confused

I am loading a very large excel flat files into Power BI and using Power Query to break the data into a fact and dimensions tables

And the usual cleaning and connecting of data

I see that Incremental Refresh (Power BI Premium ) is based on a time stamp on a loading  table so my questions are 

Does Incremental refresh work on more than one table at a time if you have several of the same tables coming from differnt sources but only one or two have changes) ?

Hows about if the structure of a tabel changess ie someone adds a column ?

How does it handle if there is alot of modeling in Power Query ? 

Is there a better alternative to handle large flat files that need to be modelled and uploaded than using incremental refresh ?

I also have a query about getting data from MS SQL into Power BI with a Data Gateway 

I read and not sure if true that the Data Gateway does not work with an SQL Stored Procedure ..is this still true ?

Can one load Temp tables directly into Power BI or would it be better to use VIEWS ?

I want to keep the SQL data strutures but has anyone any idea which is the most efficient way to get the SQL data tables through a Data Gateway into Power BI if a Premium or PRO user

Thank you