Recommended parts to repair off switch, silent switch & home button?

My power switch no longer operates correctly. I was running with the phone tucked into my shorts, and I am guessing that sweat had ruined the switch. In terms of the 'tactile' feel of the button, everything seems fine. It just doesn't do it's job properly. In fact, initially, if I pressed really hard, it would work occasionally.

What component(s) do you think I will need to repair this? I would prefer to get the parts before opening my phone up.

Secondly, on another occasion I dropped my phone (previous to the sweat damage), and the vibrate switch no longer operates correctly. When flicking the switch, nothing happens. If my phone is held in a certain way or shaken correctly, and the silent button is switched to on, it will intermittently enter silent mode for a short time. If switched to silent off, the phone functions as normal. Would I require the physical switch and housing, or just some electronic component to fix this?

Lastly, my home button has been acting oddly. I suspect it may have dirt or grime under it, as it needs to be pressed more firmly to function properly, and it feels like it gets a little bit stuck. The 'tactile' feel of the button is definitely unusual. Given that my LCD display is slightly cracked, and I will be replacing that anyway, what do you think I will require to get the home button functioning as before?

Just to clarify, I would like someone with the knowledge to take a guess at which components would be required to attempt to repair all of the above problems. I will make an assessment as to whether or not it is feasible to try to repair the phone afterwards.

Thanks for your help