Trading partner removel and its effects

My client has this scenario they want to see if they remove trading parner from the config what will be the effect of that, so i have these questions. I will appriciate if some one can guide me on this.

1 If we remove trading partner what will be the effect on standard intercompany postings, intercompany clearing, logistics posting.

2 Need a background of why trading partner is used. How trading partner is used in consolidation.

3 If trading partner is removed how we are going to clear the older invoices, effect on open items, purchase order, sales order.

4 If trading partner is removed what will be the effect on reporting, impact on payment processing.

Thanks

Krishna