Initial inventory upload- cutover activity

How the cut over is handled for the following case-

1. goods are received before the go-live date and invoice will be received after go live. Goods ordered in legacy =100 qty, received before go-live =100 qty. Invoice received after go live = 100 qty.

What will be the accounting entries and which accounts will come into picture. how the vendor invoice will be booked, as there will be no PO for it ?

2. Partial goods are recd before the go-live date and the balance qty will be recd after go live.

for example Goods ordered in legacy =100 qty, received before go-live = 50 qty. balance Qty recd after go live = 50, Invoice received after go live = 100 qty.

Is this approach right , if we create PO of the balance qty 50 in SAP, do GR for 50 pcs. if the vendor send a single invoice of 100 qty, we do MIRO for 50 qty only, how we will then handle the invoice verification of remaining 50 qty?

Please advice me of the right strategy that need to be adopted for initial upload of inventory. If I missed any other scenario that could be possible please do advise on that.