Zero knowledge of building a range - but I have other related experience, like 1) a decade or so of planning board experience, 2) observations from watching my former PA range's plans to add a longer rifle range quickly fall apart (due to environmental concerns) AND 3) being on the board of a non-profit that has successfully blocked warehousing in my area for years by raising publicity and engaging various experts to slow the developers down, etc.
Since you're in construction, you may have already anticipated this... but since you posed the question, my advice would be to first find yourself a very reputable environmental engineering firm/consultant in your area, with deep NJ DEP regulatory knowledge, to confer with right from the get-go, even as you're looking at potential properties. You would engage them to scrutinize any potential lots and, among other things, do an in-depth search for any previous mapping/surveys/studies at Fed/state/county levels. You don't want to buy a piece of property and THEN find out there's some issue with the land already identified, but buried in a county office somewhere (e.g., a tiny patch of wetlands that was identified years earlier... or a small - even intermittent - tributary that flows into another waterway deemed "sensitive"... or the lot is part of an area previously identified as a breeding site for some protected animal species... or any number of other environmental issues).
The lead contanimation that occurs at a range could certainly be raised as an issue, but particularly if any number of those special conditions just mentioned (or others) exist on the property... and that could throw a total wrench into your plans. Likewise, someone with environmental engineering expertise would also have at least an awareness of any new related environmental laws coming on to the scene. I personally think you need an expert intimately familiar with all of those issues who can raise those flags before you plunk down any money on property. You also want that person/firm to be experienced enough that they know the NJ DEP folks on a first name basis, too, so they can then grease the wheels AFTER the lot purchase. (That does not come cheap btw!)
You might be thinking "but this area is so gun-friendly, that sounds like overkill" - but remember, all you need is for one or two determined objectors to catch wind of your plans, start some grassroots PR and fundraising, and then hire their own experts, file a lawsuit, and believe me, they could tie your plans up for AGES... and you'd be left sitting on a bought-and-paid-for piece of property that you can't even do anything with! And in NJ, it is most likely the environmental issues that they would leverage to tie you up in knots. My impression is that even deep South Jersey has changed in recent years post-Covid, with an influx of new people from more northern areas - I think you can assume those folks might carry some anti-gun sentiments, too. So yeah, you COULD run into objectors, even for a relatively small range in an otherwise gun-friendly area. Better to anticipate and clear any hurdles as best you can in advance IMO.