What keyboard shortcut brings up the Powerpoint 2016 Format Shape/Object pane

See How to combine three keys as a hotkey with Autohotkey? for the first half of your question.

As far as stripping formatting, it looks to be possible with something like this (from this Stack Overflow question):

Send ^c
clipboard = "%clipboard%"
; Remove space introduced by WORD
StringReplace, clipboard, clipboard,%A_SPACE%",", All

There's also this AutoHotkey forum post about it.

EDIT: The following is in the AutoHotkey documentation on Clipboard, ClipboardAll, and OnClipboardChange:

clipboard = %clipboard% ; Convert any copied files, HTML, or other formatted text to plain text.

• Ctrl + Shift + ↑↓ change the height of the shape.
• Ctrl + Shift + ←→ change the width of the shape.

If the shape's aspect ratio is locked, changing height will change width proportionally and vice versa.

This is in PowerPoint 2010. I haven't used 2000 in a long time, but I'm fairly sure the key combos should be the same.

UPDATE: I've checked this in PowerPoint 2000, 2002, 2003 and 2007 and found it doesn't work in any of them. Apparently this feature was introduced in 2010.