1- Hardware/NAND - WiiBrew
2- nand extraction
3- It is a wii, some things do not work well
4- Yes, most apps can be installed as a channel via wad, but this waists limited space and is not preferred.
I think you have a crap load of reading to do.
Also be sure not to brick your wii as the wii has no built in recovery options should you kill it.