Fuel problem

Crank no-start. Had new fuel pump, filter, plugs and wires installed. Car ran okay for a week. Cold day and crank no-start. Can hear fuel pump prime but rail pressure at Shraeder valve seems far too low. (No pressure gauge handy, but barely squirts 0.5 inches when valve depressed.) Suspect shop did not flush tank or install pump strainer.

Connected scan tool: crank RPM's about 135-150 (so crankshaft sensor good); accurate IAT, MAF and ECT readings but "no data" for fuel rail pressure. (Scan-tool does detect fuel rail pressure on different Ford vehicle using Torque Pro app but no reading on my car). Checked spark on four of the six plug wires using in-line spark tester.

Q1: Why does Torque Pro not see rail fuel pressure?

Q2: If I check fuel pressure at Shraeder and get low (less than 25psi or even say 5-10psi). What troubleshooting steps should I take other than the obvious fuel filter replacement (again)?

Q3: Is this car a "return-less" fuel system as I suspect?

Q4: Is there some kind of fuel pressure regulator, check valve or other fuel pressure module?

Mechanic at shop has given up, but I have not. All comments very much appreciated.

P.S. I think PATS system is not the cause; theft light steady with KOEO and blinks slow three times when cranking then goes out (as I understand is normal display). At no time does theft light blink rapidly. Fairly sure this is strictly a fuel pressure problem.

Thank you!