In NetSuite FAM, how do I account for the following when creating a Lease? Prepaid Lease Payment Initial Direct Costs Lease Incentives Payment Timing for NPV calculation (In Arrears or In Advance)

FAM only accounts for leases (interest, amortization) and has nothing to do with any payments (not connected to AP at all).

But these impact the NPV calculation or initial lease liability and ROU asset

Netgain's NetLease connects to vendor bills and also offers A-Z compliance for leases. Happy to assist if needed. If you have 10+ leases, NetLease will deliver value far in excess of cost.

Yes, they will impact indeed 😞. No work around AFAIK natively.