I won’t try to speak to whether or not LGPL is acceptable for use in your company, that’s up to you. There are plenty of examples outside of the ROS community where LGPL is used in different scenarios on which you can draw experience. Other people/companies in the ROS community might be able to give their experience doing so. Also see this ROSCon talk which covers licenses in ROS and a company’s experience auditing those:
Stage is a simulator which runs in a stand alone process and communication with it is done over TCP/IP. Also, it is usually used for R&D, not product deployment, so I think that’s fine.
ivcon appears to be CPL (common public license) (see: IVCON download | SourceForge.net), but in any case it is only used as a utility to convert a mesh file from one format to another. Also, it is only used within the PR 2 description packages, which are only part of desktop-full for use in certain tutorials.
In both cases I do not believe they would be used in a production system and in both cases they are run as stand alone executables rather than used as libraries.