I like the Crucial SSDs. For the back screws and disk drive screws you’ll need a 1.25mm Phillips screwdriver, for the battery you’ll need a trilobe (sp?) driver, but those usually come with the battery. Thermal paste replacements on those laptops require removing the entire logic board and flipping it over as the CPU and GPU are on the bottom of the board. Personally, if you think the thermals are fine enough it’s probably not worth the effort to replace it. Getting the battery replaced by Apple costs $129 (not sure if that includes the cost of shipping it to their service place—https://support.apple.com/mac/repair/service). iFixit batteries are a little under $100, so I personally would rather just pay the extra $20 or so dollars just to get Apple to do it. Amazon batteries aren’t the best quality, but usually run about $30. You’ve already got the max amount of RAM, so you’re good there. This is the set of screwdrivers I have, which I got from Amazon for about $7: https://www.amazon.com/Screwdriver-Tri-Wing-Phillips-Pentalobe-Screwdrivers/dp/B07VYWDXBS You alternatively could go with the iFixit toolkit, which will be better quality and have more options for driver heads, but what I linked is more than enough to do the job for your laptop.