Changing older 3250 desktop Inspiron from Win 10 to Linux Mint

I changed my older Dell Inspiron 3250 from Win 10 to Linux Mint 21.1. After I finally changed my BIOS settings to accept Legacy device in the bootup, I was able to load and operate Linux Mint.

I am planning on using this PC to run a media server Jelly Fin backend and KODI front end. I will use my 6 Gb (Blue) SATA Data port 0 , as the applications require a higher performance port and I believe this is the boot up port. There is another SATA port directly adjacent to this blue port that is black  and #2. There is also a another SATA port # 1 and white in color next to the power supply. 

If I understand correctly the blue port 0 is 6 Gb. The other 2 ports white and black, I believe may be 3 Gb for one or both of them. I am planning (if I can work out the powering) to use all 3 Data ports.  2 SSDs (one 120 Gb and one 1 Tb) and a 1 Toshiba  1Tb drive for storing files. Any idea about the data speeds for these ports?

I am also trying to find a way to power these drives, The power supply is 180 watts. I was using a 2 way splitter cable previously to power the original Toshiba 1 Tb hard drive and a San Disk 1 Tb SSD when I was running Win 10 and it worked perfectly. I am hoping to use (from the power port on the motherboard) a 3 way splitter SATA power cable (Male 6 pin to female15 pin) to power the 2 SSDs and the Toshiba hard drive. My thinking is the power requirements for the SSd's will be small.

As to power am I being unrealistic to think the power supply will handle this?

and

Is the 6 pin connector end of the power cable a universal typical standard pin out for the motherboard single power connector? I am seeing the cables I envision using, I just want to be sure the pin outs are not a problem.

Any input as always much appreciated.

Hugh