You have submitted several questions, and some teachings from other religions that are simply human speculations about things, and as a result, are untrue. The only truth we seek is that of Jesus Christ, who alone is the Way, the Truth, and the Life (cf. John 14:6). There is not ample time to explain all aspects of Jesus, (True God and True Man), and Christianity here.
The voices which you seem to hear, if they are real and not a simple delusion are most likely demonic, and they would want to dissuade you from faith in God. Don't listen. If you are Catholic, get to Confession and receive the Eucharist, pray the Rosary and stay in the state of grace. Outside of these protections you are at risk of demonic influence. In this point of world history the demonic are running rampant and hurting many souls.
There are four last things that every Catholic needs to know: Death, Judgment, Heaven and Hell. The reality of souls that seem to be in a sort of limbo state (ghosts) are usually souls that are not damned (for example in the case of some lives cut short.) Exorcists tell us that a soul may be bound here for a time to fulfill some purpose of God — never in some scary or malicious way — as a condition before they undergo full purgation), but are in a state of being purified. Sometimes they are allowed to communicate their need for prayers and penance to mitigate their suffering, because, before they can enter Heaven, they must be completely purified. This is a painful and arduous experience, but necessary to enter the presence of God. God allows this communication, which does not extend into a sort of dialogue like mediums and diviners carry on, but simply a plea for help. If some type of conversation were to occur with these souls it would most assuredly not be of God.
There are demonic spirits that can mimic the souls of humans with the intent to deceive or lure people into sin. They are not to be entertained in any way, for they are evil and only want to hurt you.
Lastly, trees, animals, and ever-loving thing have a soul, but not a spirit, or what we would call an immortal soul.
- Trees and animals are not made in the image of God, who lives forever. Their soul, or life principle, is temporary.
- Our souls will continue on in either Heaven or Hell.