Yeah, I'm afraid that this will be most likely the case.

System Shock 2 Rebooted, a SS2 remake using the Doom 3 engine, was stopped "just 10 days after the team announced the project, [because] Electronic Arts as the owner of System Shock Intellectual Property requested to drop any association with System Shock" (ss2rebooted.tk).

Chrono Resurrection (ok, its not a shooter, but it gives a good example) was stopped too, because "Square Enix Co., Ltd issued a Cease and Desist letter" (opcoder.com), even though it looked quiet professional. When Enix interfered the project was worked on for over a year (April 2003 - September 2004).

But on the other hand, Open Outcast has not been dropped yet.

I wouldn't start such a project without asking the IP owners. All the work could be in vain otherwise.