Type 4 buses are not islands. When you perform the Tree command (which disconnects all islands), the buses BECOME type 4 (disconnected) buses. Yes, you should disconnect these buses if you're trying to solve the case.
You can disconnect buses by using the command prompt in PSSE. All you have to do is enter the command "tree" and follow the prompts.
Alternatively, this is a great introduction to Python itself. Since it's such a straightforward problem, you should be able to get the hang of creating a simple Python script. Look through the PSSE API document, and find the section which discusses the TREE command.
I will give you a couple hints to get you started:
1) Remember to import PSSPY.py at the start of your program
2) You first want to find out how many islands are in your case. The TREE command can accomplish this (using one of the APIOPT settings)
3) You want to run the Tree command as many times as you need in order to take all of the islands offline. Use a "while" loop for this
If this is a really pressing matter, let me know and I can give you a working code. Otherwise I don't mean to be cryptic, I just think that learning Python is a huge advantage when dealing with PSSE, and you're better off learning through trial and error as opposed to just using scripts other people have written.
