Hi - I hope I can help ...
Yes the Multipurpose platform is for different types of dies, including dies from other manufacturers.
I suggest you go to the Sizzix ( sizzix.com ) website and look for the die/s you like by Tim Holtz, Scroll down the page and you will see different tabs.
Click the Compatibility tab and it will give you a variety of combinations to cut the die with only the machines that they carry.
So, if you were looking at a decorative strip die, the combinations will be different for a Bigz die.
As far as chipboard goes ...Again, it depends on your type of die. If you are using a Sizzlits / Decorative Strip style die, I recommend you NEVER use chipboard. However there are people who do it and they generally use cereal or snack boxes (that's very thin chip).
Now if you are using an Originals or Bigz die, again that will vary. A simple shape, I am able to use .022, .030, .045, and sometimes .057 chipboard (depending on the die too). With more intricate designs, stay in the .022 and .030 range.
As far as the embossing folders ... You can emboss paper and cardstock and use the multipurpose platform too; again go to the Sizzix site and check compatibility.
I also recommend you do not use chip with your embossing folders, however, if you choose to use chip, use the the thin food box or .022 thickness. You can also use a product called "Paper Glide" - spritz it on LIGHTLY and it will help your chip soften and be more pliable when embossing.
Let me know if I need to expand on any of this or if any of this is helpful ....