Notebook Hardware and Upgrade Questions

Well I've just purchased an Hp Envy 17-ae108ca, i7-8550U cpu, and is currently equipt with 16gb DDR4-2400 SDRAM (2 x 8 GB) Ram, and a 1 TB 7200 Sata HD, and a Nvidia mx150 video cardwith 4GB. This unit is NOT equiped with a 4K monitor, but it is touch screen with a FHD IPS 1920 x 1080. It will be used daily for Photo editing, and film editing, and if I find it not up to the task I'd like to do some minor upgrades to the unit with memory and the hard drive.

So, I would like to know about two (2) items in question, the first is rather complicated - that being since this model came from the factory with a 1 TB HD and NO SSD - here's part a) can a 250 GB PCi-e NVMe internal SSD drive be added and used for boot up and then - part b) can I keep the 1TB drive as a backup storage Drive.

I only ask because I've talked to a number of tech's that have told me 'yes and no'. Their reasons are rather simple, "if it came from the factory with a 1TB drive, the likely hood of HP attaching (soldering) a PCi-e NVMe connector to the motherboard is slim to none."

Secondly I've seen this same model sold with 32 GB of Ram, so I'm going out on a limb and concluding that these are 2 x 16 GB memory cards and not 4 x 8 GB cards. So the question is, how many slots are available for memory on this platform? I'm hoping it's not two (2) slots if you purchased a unit that has 16GB, and four (4) slots if you purchased a unit that has 32GB. 

Obviously by the questions, you should be aware that the laptop will be arriving on Wed. or Thurs. so it's not yet in my possession.

Any help would be appreciated, many thanks in advance - E-jay