The 2N3819 Jfet has an IDSS of from 2mA to 20mA.
A 2N5458 has an IDSS of from 2mA to 9mA and can be used,
a 2N5459 has an IDSS of from 4mA to 16mA and can be used,
a 2N5485 has an IDSS of from 4mA to 10mA and can be used,
and a 2N5486 has an IDSS of from 8mA to 20mA and can be used.
Yes. The original post wasn't quite clear what should be placed instead of 2N3819.
2N3819 is a popular and well available JFET, so I don't see a reason to replace it with a different type. I would probably use BF245C (or BFR30 SMD type), but almost any NJFET can do. If a larger input voltage level should be processed without distortion, higher Vgs,off values are necessary. A BJT emitter follower gives better linearity but higher part count.