LvPECL TX and LVDS RX
Firstly LVDS and RS-485/RS-422 are generally different things. While RS-485 is a low voltage differential signalling standard, LVDS as a standard is quite different.

In the case of RS-485/RS-422, yes you can directly connect an LVPECL transmitter to an RS-485/422 receiver (TI App Note AN-972). RS-485 receivers have a very wide common mode offset tolerance that will happily cope with the LVPECL common mode offset. The LVPECL differential voltage is also well within range for an RS-485 receiver.
For your case of LVPECL to RS-485, you will need to use the correct termination for your receiver. Do not use the parallel 120R termination that you would use for RS-485. Instead you should use an LVPECL termination scheme which terminates each line via a 50R resistor to VCC-2V (for 3.3V LVPECL, that would be 1.3V). Alternatively you can use a Y termination such as:

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Going the other way (RS-485 Tx to LVPECL Rx) would not be advisable.

In the case of LVDS, the receivers typically require specifically a 1.2V/1.25V common mode offset, and a 400mV differential voltage. An LVPECL transmitter uses a 2V common mode offset which would be out of range for most LVDS receivers, and the 800mV typical differential voltage is possibly also too high.