I’ve done some battery replacements in the past and sometimes it will take a few discharge and charge cycles for the battery to be properly identified. If the problems don’t work themselves out then I think a reinstall of the OS would do it some good. I suppose you could unplug then plug in the battery or test it with a different battery. Good luck!
The best drop in supported CPU was the Intel Core Duo X7900 which can be found for $20 - $50 but the Intel Core Duo T7800 is also supported and can normally found cheaper. If you want you can fiddle with newer operating systems you will have to get a T9300 or T9500 but there have been issues reported. More can be found in this link- replacing X7900 to T9300 for macOS Sierra install Is it worth it?
It sounds like the battery in the phone is bad. If the phone works perfectly fine on the charger but dies when you take it off then battery is bad. Over time the battery will degrade with every charge and discharge. You should see about getting the battery replaced. Good luck!
Sometimes I have to preform a hard reset on my bluetooth speaker for it to connect to any device. On your JBL Charge 4 you have to (1) Turn on the speaker (2) Press and hold the volume up (plus) and the play button (triangle) for about 5-10 seconds. (I’d just hold it down until you get tired of it or it turns off) After this you should remove the speaker from any bluetooth paired list and pair it again to your devices. Good luck! https://thedroidguy.com/how-to-fix-jbl-charge-4-bluetooth-not-connecting-problem-1151271
You can force off the iPad if you hold down the power button and the home button for about 3-5 seconds. If you hold it down for long then it might restart. While the iPad is off if you plug it in it will turn itself back on. Good luck with getting the screen fixed!
If the video I found is the model you have then I would say the CPU is not upgradable or it is not easily upgradable. The CPU is soldered onto the motherboard like most laptops today. It’s extremely rare to find a laptop where the CPU or GPU can be upgraded. If your computer is acting slow then a good upgrade I can recommend is an SSD or to clean the computer of dust and derby. Having at least 8Gb of RAM is a must but having 16Gb is better. Good luck! Video of disassembly- https://www.youtube.com/watch?v=VElpRsnt...
By “service battery” are you referring to the service battery on iPhones and iPads? That is not really a thing on macs. It shouldn’t show up as long as you get a battery from any reputable seller. Good luck! Link to iFixit battery- MacBook 13" Unibody (A1342 Late 2009-Mid 2010) Battery
Like on most modern tablets it looks like the screen is glued together. The glass, the digitizer and the LCD are all glued together and are extremely difficult to separate without the proper tools. It would be easiest to replace the whole display. Good luck! Video on replacing the screen- https://www.youtube.com/watch?v=O2xg-hOWeLw
Take pictures and report this to eBay and the seller. There is not much you can do about the phone being stolen because it sounds like you didn’t get it liked to your account so unfortunately it sounds like the phone is gone. Stolen phones are hard to get back from my experience. I would also contact whatever you used to make the purchase and see if they have a program that protects you against online purchases where you don’t get your product. Good luck!
First off I would see if you are still under Apple’s Warranty or have Apple Care at this website. If you aren’t under warranty and you don’t want to spend the money taking it somewhere you can fix the button for the volume down or replace the cable. Sometimes the little black part on the button falls off and doesn’t allow you to press the button anymore. I can’t tell what iPad you have so I have listed the parts and breakdowns for both the iPad 7th gen and the iPad Air 3rd gen. From my experience iPads are one of the hardest apple products to work on so good luck! https://checkcoverage.apple.com iPad Air 3 Teardown iPad Air 3 Volume Button Cable iPad 7 Teardown iPad 7 Volume Control Cable