yes
You can use a slow cooker with either frozen or defrosted meat. The recipe should state which you use or the cooking time and temperature will have to be adjusted. Frozen meatballs are excellent in a slow cooker.
A crock pot and a slow cooker are the same thing. You can use the same recipes for these two devices without a problem. A crock pot and a slow cooker perform the same functions.
If you use the right plug, then yes
Use a dutch oven in the oven and you would get the same result, it would heat all around like the slow cooker. Use it on top of the stove and it's only hot on the bottom and would tend to stick and scorch. Also, the slow cooker is not going to heat up the kitchen like using the oven will.
No, silicone bakeware is not meant for use in a slow cooker. Consult with your owner's manual for what bakeware (if any) can be used.
rice cooker
Yes, you can use a slow cooker base (not crock pot) as a warming tray. Of course, the base is not very large, but it can be used as a warmer. You can also, keep mashed potatoes warm for up to an hour in the slow cooker pot on Low.
Slow cookers use very little electricity and are very energy efficient.
Try canned diced tomatos.
If you leave lights on when you are not using them and leave the TV on when you are not watching it, you are using too much electricity. You can actually cut your electric use and bill by shutting off lights when you are not using them, turning off appliances, including computers.
Yes you can still use the slow cooker with the pot roast recipe. If you want it finished quickly, use the higher setting, if you want to let it stand and cook for ten hours, use the lower setting. They both will come out with the same result.... tasting so delicious!