OK, besides pointing out that the version of NetOps/NFA that you are using is unsupported for several years - which I presume you already know and probably the reason that you are using the forums - I would suggest that you have a look at it and make sure that it matches your Portal version. There were a lot of issues that have been resolved in NFA since that release...
Back to the question - Juniper devices output jFlow. It is their own version of IPFIX. However, for all/most intents and purposes, it is still a flow protocol that is read by NFA (and ReporterAnalyzer before it). I have had plenty of customers in the past with Juniper devices outputing into NFA without issue.
For configuration of jFlow output, I would suggest looking at Junipers docs. The same rules of thumb apply for configuring them along the lines of what you would have done for a Cisco - as in flow ingress/egress turned on, don't use sampling, etc. etc.
On the NFA side of things, the device will appear just like any of the other devices you have seen before. There shouldn't be a need to have a dedicated Harvester for them (though up to you as to whether you want to do that). AFAIK, you do NOT need to "lock flow settings" on the Harvester - say if you were using Netflow v5/v7 then you might have to do this.