The Xiaomi Redmi Pad Pro supports the Xiaomi Focus Pen as the official stylus.
There is no information on whether it is also compatible with other suppliers.

Whether a stylus from a third-party provider such as the Samsung S Pen or a Lenovo stylus is compatible depends on the technology used:

- Samsung S Pen uses Wacom EMR technology, which is mostly not compatible with Xiaomi tablets.
- Lenovo pens use different technologies (AES, EMR or USI), which also do not necessarily work with Xiaomi devices.

If you want to use a third-party pen, you should look for USI or passive capacitive pens, as some Xiaomi devices may work with them. However, a full-fledged replacement with pressure sensitivity and tilt detection is unlikely.

Recommendation:
For the best functionality, you should use the Xiaomi Focus Pen.

I don't know exactly. I don't use a pen for this tablet. But I can well imagine that it could also work with a pen from a third-party supplier.
Scrolling with my finger works perfectly.
I even tap a password on the display with my finger and paste it (from the clipboard) into the corresponding field!

Unfortunately I can't answer this question, I haven't tried it yet.