Hello, alficles-
If your scripts are mostly self-contained, you should not need to do any such calls to other initialization scripts. That is, if you are not trying to use functions defined in the init script to which you alluded (like the Get-InstallPath or the LoadSnapins functions), you can just load the necessary snapin(s) from within your own script.
For example, if your script uses standard, core VMware VimAutomation cmdlets, you can just have your script load the appropriate PSSnapin if it is not already loaded. And, for not leaving PSSnapins loaded/lingering, you can just have the script unload the given PSSnapin if it had to load said PSSnapin. Something like:
## start of script: add PSSnapin if not already loaded
if ((Get-PSSnapin-NameVMware.VimAutomation.Core-ErrorActionSilentlyContinue) -eq$null ) {Add-PsSnapinVMware.VimAutomation.Core; $bSnapinAdded=$true}
## do all the good script stuff here
## stuff
## ...
## stuff
## at end of script, if given PSSnapin had to be loaded at start, unload it here
if ($bSnapinAdded) {Remove-PSSnapinVMware.VimAutomation.Core}
So, just load the PSSnapins that the script needs (if not already loaded), and unload them at the end if the script loaded them. Make sense?