How would I go about creating a filename with invalid characters such as :?> ?

Unfortunately, you cannot use the reserved characters when creating folders or files due to them being part of system functions.

What I recommend you do is look through the Character Map application - You can go to run and type charmap.

from here, you may be able to find alternate symbols that look the same, for example:

(copy and paste these, you will see that they are different)

Instead of forward slash / - you can use a division symbol ∕

Instead of Colon : - you can use the modifier letter colon ꞉

and so on!

You can boot from a Linux disk (such as Knoppix), and mount the NTFS partition.

Linux has much less restrictions on files names, and will let you create such names (I have tried it).