Islams is not a word. Followers of Islam are called Muslims.
1. Islam describes itself as healing and nourishing, in this life and the Next. That does not mean that there is no hardship in the world, or that people will never face any trials. Rather Islam tells human beings that both blessings and hardship in this world are ephemeral - they do not last. Blessings and hardships are identical in the sense that they originate from the same source - God. It is through the ability to welcome hardship with patience, and endure blessings with gratitude, that a person advances spiritually.
"For truly with hardship comes ease; and truly with hardship comes ease." (Surat al-Inshirah: 5-6)
2. Yes, Islam states that the soul persists after death. The body will be physically resurrected on the Day of Judgement.
3. Best to contact a vet who is qualified to make the judgement. But kindness towards animals is praised in Islam.
"A prostitute was forgiven by Allah, because, upon passing by a panting dog near a well and seeing that the dog was about to die of thirst, she took off her shoe, and tying it with her head-cover she drew out some water for it. So, Allah forgave her because of that." Narrated by Abu Hurayra, in Bukhari 4:538
4. Death is something every human soul must taste, but God is capable of changing us in ways we do not comprehend, i.e. giving us eternity in the Hereafter.
5. Suicide is forbidden as it represents a loss of hope in God's love and mercy. Suicide is considered a major sin, but does not entail disbelief.
6. "Human beings should not interfere in this." This is a misunderstanding, as human beings are simply incapable of interfering. In Islam, absolutely nothing can occur without the decree of God. When and how you will die is known and determined already, whatever your chosen actions. Killing human beings is permitted if they pose a threat to your life and there is no other way to protect yourself, or they have violated the Sacred Law on certain issues. For example, in some instances, the death penalty may be enforced on a murderer.
7. That verse refers to murder, not all forms of killing. It is permitted to fight in self-defence.
"And slay them wherever ye catch them, and turn them out from where they have turned you out... and fight them on until there is no more tumult or oppression, and there prevail justice and faith in God. But if they cease, let there be no hostility except to those who practise oppression." - [Surah al-Baqarah 2:191-193]
8. No, I don't.
9. There are often misconceptions as to what Shariah Law constitutes. Shariah Law comprises everything from aspects of personal, everyday worship in terms of how you pray and give charity, to broad principles for criminal codes and financial dealings.
Shariah Law is also not a monolithic body that is universally agreed upon by all Muslims. Inside Sunni Islam alone, there are 4 broad schools of jurisprudential methodology called madhhabs, and even within those schools there are plenty of disagreements. So, two Muslim jurists can view the same subject and reach very different conclusions, in the same way that two lawyers in the United States might view a topic and say this action is legal or illegal. But in Islam, "differences of opinion are a mercy", according to the Prophet.
The point of all this? Shariah Law can be interpreted in many ways. The roots of it are in the Qur'an and the Sunnah, but with time it can be understood in different ways. For example, there is a Qur'anic precept that we must not harm ourselves. Smoking was not known of as harmful a few centuries ago, so Muslim scholars called it permissible. Now that it is known to cause medical harm, it is called forbidden and sinful. That is an example of how the precepts of the Shariah Law endure and remain the same, but the rulings update.
10. Both, however, God ultimately determines what is right or wrong. The Qur'an, Prophetic Tradition (sunna), consensus (ijma) and independent reasoning (qiyas) are the basis of Shariah Law, interpreted by Muslim scholars. Some of those interpretations are correct, and some are not. So long as the scholar truly strives to understand the truth correctly, and do good, they will be rewarded by God for their efforts.

