A:AnswerA power cable, available from your PSU in most cases, and a SATA connector, usually available with your motherboard. Other than that, no cables needed.
A:AnswerThose cables aren't really where any magic happens. It either works or not. It's a binary condition. Just get something close to the length you need so you aren't creating a cooling problem for the case.
A:AnswerIt's a SSD-solid state drive not a harddrive but yes you should be able to use this how you described but you'll have to go into your storage on your computer and configure the SSD and give it a letter of your choosing
A:AnswerAs long as the boot drive is a 2.5" SATA based (laptop) hard drive, or has space to install one, then yes, it will work. Obviously it won't be as fast as an m.2 NVMe SSD, but it will definitely run rings most platter/rotational hard drives, especially the ones used in most consumer grade laptops.