these ICs are BGA and difficult to replace with equipment. Sorry but impossible to DIY these days. Even then there is no guarantee the extra memory is going to be addressable from the software without some firmware hack. Let's just hope Google managed to do what this was suppose to do.. challenge other manufacturer's to outdo them in feature and price
The bottom right 4 pins are connecting the Mobo to the docking pins which can see in Step 12. The top 24pin array is typical layout for smtc connector so not likely for a hidden Micro SD socket no go :(