Suggestion for upgrade the Hp Pavilion 15-bc504tx

[Satyam_chn]

Hi, I want to upgrade my Hp Laptop ram and SSD.  Here is the manual of my Laptop (HP Pavilion 15-bc504tx

http://h10032.www1.hp.com/ctg/Manual/c06325755.pdf

Linux command shows max supported memory is 32 GB whereas the manual says max supported memory for each slot is 8GB. I am confused should I go for 16*2 or 8*2.

satyam@hp-pavilion:~$ sudo dmidecode -t 16
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 3.2.0 present.

Handle 0x0011, DMI type 16, 23 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 32 GB
	Error Information Handle: Not Provided
	Number Of Devices: 2

Current Ram configuration: Samsung M471A1K43CB1-CTD 2666 mhz  260 pin 1.2v 8 gb single channel Ram

I have the following question regarding Ram:

1) Some ram with same specs is available with 256 pin or 1.35 v or higher clock speed 3120 mhz. Can I go for those ?

2) Maximum memory compatible with my laptop. For coding purpose, I need a higher ram, more than 16 GB.

Coming to M.2 slot:

I watched some youtube videos on M.2 slot and it confused me a lot. I need the following information:

1) What are information should I look for before buying SSD  and  how ?

2) Does my laptop support M.2 NVME (PCIe Gen 3.0 x 4) SSD ?

3) Do I need to upgrade my BIOS for the above SSD ? The current bios is F.05 and I don't know whether it has supports for NVMe.

 I am looking to buy Samsung 970 EVO Plus 250 GB PCIe NVMe M.2 (2280) Solid State Drive (SSD) (MZ-V7S250),  would that be compatible with my laptop ?

Actually, I have too much confusion regarding the compatibility of laptop with the new ram and SSD, so I asked a lot of questions. I would be thankful for any help. 

P.S. If the aforementioned product is not compatible, can you suggest what is maximum specs for SSD or Ram is compatible with my laptop ?