RasPi Touch for Photo Backup while Traveling

[lhubschmid]

Dear RasPi friends,

Issue:
I am currently traveling in South America, and right now, for backing up the Photos of my Camera I have to use a OTG SD Card Reader, copy the Photos to my internal Smartphone storage, and from there copy the Photos to a Backup SD card, and copy them as well to my "Upload Smartphone" (cheap Nokia 1), which can stay in the Hotel during the day to upload the Photos via Wi-Fi to my Nextcloud instance. This always takes some time (OTG and write to SD cards are not that fast, limited internal storage requieres copying in multiple batches, etc.).

Idea:
For my next journey, use a RasPi 3 something. Use a small USB Stick (16GB) as Boot Drive for Raspbian OS, use a mSATA Adapter Module and a mSATA SSD (128GB+) as internal storage, leave the SD card slot free. Add a small touch screen (I think the ones I found were around 3") to have it as compact as possible.
Write a small application (??) for the touch screen (fullscreen on start) which basically has buttons for:
- Connect/Disconnect to/from Hotel WiFi (with entering passphrase)
- Start/Pause/Stop Copy Photos from SD card slot (Camera SD card) to internal storage (SSD) (basically initiate/signaling to rsync script)
- Start/Pause/Stop Upload Photos to Server (basically initiate/signaling to rsync script)
- Unmount SD Card
- Properly Shutdown RasPi

Questions:
1) Is it possible to combine an mSATA Adapter Module with a Touch Screen? Which modules can you recommend?
2) Is there a case which fits the above?
3) Is there any starting point on how to write a fullscreen touch application for the Raspbian OS?
4) Can the SD card slot be used hot plug (insert/remove SD card while running)?
5) Any other sugestion?

Many thanks for your help,
Lukas