After executing
LazarusIDE.DoOpenProjectFile('SomeProjectName.lpr',
[ofProjectLoading,ofOnlyIfExists,ofConvertMacros,ofDoLoadResource]);
How can I show the project inspector and code editor ?
What exactly are you trying to achieve? It looks like you are trying to open a project from a package via the IDE and package interface. In that case the OI and CodeEditor should be already visible.
I did not checked, but I'm almost certain that accessing the OI via the IDEInterface is not possible, though the interface can be extended if there is a good reason for it.