Autistic kids and teens do want friends, the idea that autistic people are anti-social is false. Autistic people often want friends but struggle to make and maintain friendships.
Yes, Autistic people can 'make' a child just like anyone else.Autism is a neurological variation, it doesn't prevent someone from reproducing just like a person of any other neurology. Autistic people are more likely to have Autistic offspring, especially if both mother and father are Autistic, but can also have children of different neurologies.
Autism Spectrum Disorder is a neurological condition, autistic people are born autistic - we do not know why people are autistic.
Often autistic people can spot autism in others, given symptoms of autism or that many autistic people are a little unusual - I'm autistic and have found over the years that we autistic people tend to be naturally drawn to each other, which is a nice thought. If you are seeking out other autistic people it is best to join an online autism community such as WrongPlanet - although like any other online community there can be a fair share of drama, most members are autistic so you can make friends with them online or look for other autistic people living close to you. Many areas have an autism group of some sort, for example where I live we have two autism social groups - try searching online for such groups, sites such as Meetup, and try finding local autism schools or groups to contact to ask if they know of any such groups suitable for you.
A lot of Autistic people have severe sleeping problems. Autistic people tend to have lower levels of melatonin which is the chemical responsible for telling the body when to sleep, Autistic people can often get caught-up in what they're doing so lose track of time, Executive Dysfunction can make it hard to keep a bedtime routine, and Autism people often have problems 'turning off' their brain in order to sleep. Some autistic people have no problems, but most Autistic people will experience sleeping problems at least once during their lives.
Firstly, it's offensive for you to imply that autistic people are abnormal - autistic people are different to neurotypical people, not less than. A person is born autistic, it is not something that happens to 'normal' people or something that you turn into, you are always autistic.
You can't - autism is an absolute, you are either autistic or you are not and there is no way that a person can become 'less autistic'. A person with autism can improve in areas such as commnuication, social skills, and functioning, this tends to happen naturally as autistic people get older and learn new skills, but it is helped by supporting and understanding the autistic person.
Yes, autistic children can be taught in mainstream schools. Most autistic children are likely to be mainstreamed, one reason being that autistic children thrive in mainstream school when they're allowed to learn and interact with their neurotypical peers. Often in special education autistic children aren't challenged enough, this is true in mainstream schools too but worse in special education.
No, not all Autistic children are savants. Many Savants are Autistic, but most Autistic people are as normal as Neurotypical people with no particularly special talents.
No, not all autistic people lack a sense of humour. There is a saying in the autism community: once you've met one autistic person...you've met one autistic person. autistic people are as different and varied as neurotypical people.
In short, very differently. In England we have the Autism Act which ensures all Autistic people have a pathway to diagnosis, although there's limited support for Autistic people government staff are supposed to be trained to understand Autistic people, Autistic people don't face healthcare discrimination like in the US where they may be expected to pay more for health insurance, and there are anti-discrimination laws in place. In England we tend to me a lot more accepting of Autistic people. In America there is a lot of scare tactics being used by people like Autism Speaks to make money out of families with Autistic children - Autistic parents are expected to spend thousands and allow their children to be tortured to make them 'normal'. Autistic people can face a lot more discrimination both in terms of employment and healthcare, and generally within society people consider Autistic people to be less than neurotypical people and there are stereotypes about Autistic people being mass shooters or otherwise violent. Often Autistic children are murdered by their parents and there is such a problem of ableism around Autism that people support the murders. I'm Autistic and live in the UK, but I will be moving to the US to live with my Autistic husband - the difference in attitudes between the two countries is as different as chalk and cheese.
Public schools. The more social situations they encounter, the more used to them they will become. You dont want to keep your child at home for years, and them expect them to walk out into the world and be fine.