User Manual Acer CB5-132T-C1LK Chromebook R 11 Convertible

I just purchased this model, CB3-131-C8GZ Clamshell color from Amazon. It does support Android - the Google Play Store icon sits right on the desktop. It shows all the apps and install them the regular Android way. I try some of them: Reader, Pictures, etc - they work properly, the navigation within apps is a bit different though: they can see the file that are in the Download folder only. They do not see the SD card. This may improve with time. Some of the most recent apps are still missing from the Google play here. The screen rotation in the Tablet mode is supported by all apps I tried.

Since it only does WiFi, you would have to set your smartphone to "hot spot" and then connect the Chrombook WiFi to the phone WiFi etc.

If that size card is an issue, use a micro sized usb 3.0 drive. They come in capacities up to 522GB at this time with 1 and 2 TB cards in prototype stage..
That the SD slot would have a capacity lower than the maximum permitted by the capability of the SD specification or FAT32 format namespace limits: (4 GB maximum file size, 8 TB maximum partition size) would be a chipset limitation. Chromeboxes can have 8GB of RAM, enough to handle a 4GB file.