Soul of a person who committed suicide roaming the earth

Q: Is there any ruling that someone who committed suicide or accidental brutal death or anyone purposely killed him either ways, so their soul is roaming that place and makes hurdles to the passers and if it likes someone, it possesses the body. As this is a worldly talking that a person is been killed or died in accident or suicide...and he later possessed someones body....and troubles....so is this correct.... 

Qadha for not fasting

Q: I am a student aged 20 yrs old. I have missed a lot of fasts almost all during past months of ramadan except this one. With Allah's grace, I came very close to islam this year, praying regularly even the tahajjud prayer and fasting almost daily. I have read about the compensation of breaking fasts that is 60 foods for poors or 60 days fasting for 1 fast. As I am a student so I cant afford food for poor people so I fasted almost 4 months consecutively as a compensation for 2 fasts but then after some research I came to know that the compensation for fasting is only for those who "break" it by intercourse, eating e.t.c and not for those who "leave" them. For every fast a person left out of ignorance in past, he only have to fast 1 day for 1 fast. My question here is that, I have fasted 4 months with the intention (niyya) of compensation for 2 fasts but is it right that those fasts can be recorded as compensation for 4 months of fasting (1 fast for 1 day) so i have completed the compensation for 4 months of ramadan fasting that I have left in the past and not just the 2 days even if I don't have the intention of every fast to be for 1 fast i left before.