PC Tech Thread

I want to upgrade my old laptop which used to be my folks and have some questions.

I want to:

1. change the HDD to SSD,
   
2. increase the RAM,
   
3. Update the graphics card software (which I seem to struggle installing driver updates for - it's got two, idk if that's normal)
   
4. Fresh install of everything - W10 with Ubuntu dual boot
   
   

Questions:
A. If I keep the old HDD can it just be popped back in anytime in the possible but rare situation my folks need something from it, or even better can I keep it in one of those caddies and boot from it if I hit esc or whatever on startup

B. Is there a particular order I should do everything? Ram > SSD > graphics software

C. Is there anything else I need to think about?

Cheers.