The apps you're trying to install are probably not compatible with android 6 or 7, which is what your tablet is running. You could install a custom rom of a newer version of android, or use older versions of the apps you can't install.
The ssd is most likely non replaceable like @visualwit suggested, however for some reason it has a normal laptop ram slot. So you could upgrade to 8gb of ddr3. If you want more storage your best option is to keep a high capacity sd card or flash drive in it.
Checking the capacitors is a good idea, specifically the 3 or 4 on the video circuit. Before you take it apart leave it connected to the tv and turned on for 5-10 minutes, if you start to see a faint image then those caps are likely the problem. Or try a different tv that displays a no signal error and see if the wii even outputs anything.
Resetting it will delete all your data. First turn it all the way off, then hold down both volume and power until the screen lights up, then you should see a menu with options such as factory reset, clear cache, etc. Use the volume keys to move to factory reset, then press power to select and wait for it to reboot. If both volume keys at once does not work try only holding volume up and power or volume down and power
That amazon cable for the ps2/3 has both component and composite, also known as rgb and rca/av, Your switcher only supports rgb video, which you seem to have confused with rca. You need to plug the green, blue, and red from the ps2 into the green blue and red ports on the switcher. You have audio plugged in correctly though.
I'm pretty sure every type 600 polaroid camera is built the same so this should work with other 600 cameras. I followed this guide for my polaroid 640 land camera and it was exactly the same.