2004 Jeep Grand Cherokee Cranks But Won't Start

So my uncle is giving me an old 2004 Jeep Grand Cherokee that has been
sitting unused for years. So far, to try to get it up and running we have
replaced the battery, fuel pump, and fuel filter, and a cam shaft sensor (after
getting a code telling us to) The car will still not start. Now my uncle knows a
few things about cars (but isn't exactly a mechanic), so to do some
troubleshooting he sprayed some kind of can (starter fluid, maybe?) into
some air intake and it sounded like it wanted to start, but once the car ate up
whatever it was he sprayed it went back to just cranking and not starting. We
know fuel is getting to the fuel injector rail because we took off the fuel line
and turned the key and fuel came out. My uncle thinks is that there is some
reason that fuel is not getting past the fuel injectors for some reason
preventing the car from getting fuel to the right places and starting. A few
reasons he thought of was we installed the fuel pump wrong, it was the
wrong pump (got it off of amazon for relatively cheap, so this is a possibility),
or whatever is controlling the fuel injectors stopped working or has a bad
wire.

Does any of this sound right? I'm trying not to spend too much money and
the stuff we can do ourselves instead of towing it to a mechanic is more
beneficial. Any ideas on what could be causing the car not to start other than
what was stated above?

Thanks in advance