Is that correct?
Sure, you are totally correct about all of it. Despite the fact that this is a link to a great 2014 upgrade thread, you should probably just get a 2012 i7 for your intended tasks. Apple PCIe flex cable part number for Mac mini 2014
I will find some more sources for 2012 upgrade kits if you want. Offhand OWC http://eshop.macsales.com/item/OWC/DIYIMM11D2/ and iFixit https://www.ifixit.com/Guide/Mac+Mini+Late+2012+Hard+Drive+Replacement/11716 are two popular options.