Will the custom column values will change with updated values from data source

Yes, the values will change if the data source is refreshed. 

You can create a column across the table. But they will be pre-calculated. means will not have any imapct if choose any variable

refer:

https://www.sqlbi.com/articles/calculated-columns-and-measures-in-dax/

In table one using table 2

New column in Table 1 = maxx(filter(table2,table1[customer] = table2[customer] && table2[option]="construction",table2[value])

New column in Table 1 = maxx(filter(table2,table1[Attribute] = table2[name] && table1[project] = table2[project]),table2[name]

In table 1 using table 1

new Column =
LOOKUPVALUE('Table'[Lot No.], 'Table'[Entry Type], "Output", 'Table'[Document No.], firstnonbank('Table'[Document No.],true()))
OR
new Column =
minx(filter('Table', 'Table'[Entry Type]= "Output" && 'Table'[Document No.]= earlier('Table'[Document No.])),'Table'[Lot No.])

Appreciate your Kudos.