I do not know if you can use it with and iPad Mini 1. I don't have any experience with that iPad so I can't say.
Your other questions I can answer.
I jailbroke 9.3.5 with PhoenixPWN and while looking for something else came across this:
Actual Link
In the description for the video there is a zip file for downloading. That has all the stuff you are going to need to do this. There'a readme file inside and it's got the instructions for the part after the jailbreak - so if you don't care to watch the video you can just follow that.
I did not need blobs. They are included in the IPSW that's within the ZIP file you download. I believe it's because 6.1.3 is still being signed for certain devices, but IDK. It worked in any case.
And it's not Coolbooter. It's a downgrade. Once you're back on 6.1.3 you're back on 6.1.3.
The directions use idevicerestore.