S Pen Interoperability: SGN12 with SGN5; and SGN5 OS Upgrade

A pre-sales query to Samsung UK Product Support

EDIT: Predicated on further research, I've changed the variant below from I to C, since it is the N920C variant which is fully compatible with all of the UK network provider's 3G and 4G band frequencies.
● source » https://www.frequencycheck.com/compatibility/eOkrU47/samsung-note-5-sm-n920c/united-kingdom

 
Dear Citizen,

I own a Samsung Galaxy Note Pro 12.2 SM-P900 tablet (SGN12) and I'm looking to upgrade the stylus-based phablet which I use alongside it. I'm currently using a 2013-vintage ASUS Fonepad Note FHD 6 (AFN6) stylus-based phablet, but it's stuck on Android 4.4, so I'm aiming to acquire a more modern stylus-based phablet that can run on Android 6.0.1.

Until recently, that was going to be a Samsung Galaxy Note 7 (for the demise of which I send my commiserations) - since that's no longer an option, I am now weighing up the pros and cons of these two candidates, neither of which have been officially released in the UK, yet both of which I can grey import from overseas via an eBay/Amazon order or similar:

(1) LG Stylus 2 Plus K535N or K535T - released July 2016 with Android 6.0.1 out of the box
● about » http://www.gsmarena.com/lg_stylus_2_plus-8079.php

(2) Samsung Galaxy Note 5 N920C (SGN5) - released August 2015 with Android 5.1.1 out of the box
● about » http://www.gsmarena.com/samsung_galaxy_note5-7431.php

So I'd like to ask for help from you in answering a couple of questions about the Samsung Galaxy Note 5 N920C:

Q1. S Pen Interoperability

I mostly use 12" tablet and 6" phablet alongside each other every day, in a two-screen setup - but the SGN12's S Pen doesn't work on the AFN6's screen, while the AFN6's stylus doesn't work on the SGN12's screen... so currently I have to put down one stylus and pick up the other one to switch between using tablet and phablet: needless to say, this marked lack of stylus interoperability is NOT an ideal situation.

Question #1: Are the S Pens of the SGN12 and SGN5 interoperable?
That is, does both the SGN12's S Pen work on the SGN5's screen, and the SGN5's S Pen work on the SGN12's screen?

Q2. Stock Samsung Android Upgrade

For your SGN5, GSM Arena notes "OS:  Android OS, v5.1.1 (Lollipop), upgradable to v6.0.1 (Marshmallow)".

Question #2: If I buy a new or second-hand Samsung Galaxy Note 5 N920C running Android 5.1.1, will 'Settings > About device > Software updates' allow me to install a Samsung OTA stock OS upgrade to Android 6.0.1?

Please send your answers by email to:

"Tim Jones" <tim.dalinian.jones@googlemail.com>

Thanks in advance for your time and attention. I look forward to hearing from you soon.

Best regards,

Tim Jones