reply to fukitol
Re: Free or low-cost inter-NPA forwarding? What phone service(s) and equipment does the new company have? If their PBX is IP-capable, getting them some Internet service may be the best solution.
Else, if they have service from a CLEC via PRI, you may be able to hand calls to the carrier by IP, at a low cost. Or, the CLEC may be able to provide the 212 numbers with unlimited incoming (but at substantial cost per channel).
Assuming that the 212 is with Verizon (and the 516 number is local), changing the 212 to an RCF (remote call forward) may avoid per minute charges, though the monthly may be steep, depending on the number of concurrent calls that you need.
If all else fails, expect to pay about $0.005/min. for the outbound leg of your forwarding setup.