With regard to EPS export omitting invisible objects: my guess is that this is expected and useful behavior for normal PS/EPS export since transparency is not supported by PS/EPS (why then would you want or expect transparent objects to be exported?).
If you consider it a bug, I think it should be reported separately as request to include invisible objects in PS/EPS export (if this is doable at all - I do not know specifics of the PostScript specification).
With regard to EPS export omitting invisible objects: my guess is that this is expected and useful behavior for normal PS/EPS export since transparency is not supported by PS/EPS (why then would you want or expect transparent objects to be exported?).
If you consider it a bug, I think it should be reported separately as request to include invisible objects in PS/EPS export (if this is doable at all - I do not know specifics of the PostScript specification).