Usually, bootbank after installation comes with a minimum of 100MB free space. I am very curious on what vib you are trying to use that is higher than 100MB. 
And regarding your questions:
- Is there a way to resize the bootbank partition? I have looked for answers and couldn't find any.
Nope.you cant.
- My preferred way was to install the VIB on the local drive and not on the bootbank partition. Is it even possible?
You may place the vib in the Local drive, but it gets installed in the bootbank only. So nope
My last question is about running scripts after VIB installation: Is there a way to run commands after installing the VIB and not just copying files?
You can run scripts after vib installation, however, if your vib installation is requiring a reboot, then running a script which changes the kernel or any other parameter might not be advisable