Here are the answers to 6 major cat breed questions.
Which cat breeds are the friendliest?

Friendliness depends mainly upon socialisation which cuts across the breeds so it is an individual cat thing. However, if pressed I’d nominate the Maine Coon because according to Gloria Stephens, ‘..some develop such a strong attachment to their female owners that they become recalcitrant when the female owner is away’. Another breed worth nominating under this heading might be the famous Ragdoll, ‘they are a friendly, affectionate, and intelligent breed of cat, and they truly love human company’.
I have selected 2 breeds. They are others so it’s down to personal choice. The key factor is to select the individual cat not the breed. All cats of any breed should be bred and socialised to be friendly otherwise they’d be a lousy pet.
Which cat breeds shed the least?

All domestic cats shed hair in the same way. Logic lends to the theory that shorthaired cats shed less hair (in terms of weight!) than the longhairs. So Siamese cats should shed less than Persians as an example. The hairless cats will shed the least for obvious reasons. These are the Sphynx, Don Sphynx and the nearly hairless Peterbald. I’d nominate the Sphynx which is an intelligent and interesting cat with a particular personality but as they have no fur to protect them precautions need to be in place with respect to exposure to the elements.
Which cat breeds live the longest?

You won’t find data on this so you have to work backwards. Which cat breeds have the least inherited diseases? That might be a good starting point because obviously longevity is directly linked to health. On this site I discuss inherited illnesses of the breeds. My research tells me that of the well-known breeds, the Japanese Bobtail, Nebelung, Pixiebob and Peterbald have no reported genetic health issues although this list is by no means complete. At the other end of the spectrum the Siamese and the Persian have the biggest list of inherited diseases but this may be because they are the most studied breeds. That said I’d avoid them if health is an issue for you.
Which cat breed is most like a dog?

Dog-like cats are much discussed. Again it is largely down to individual personalities. But one slightly rare cat breed comes to mind immediately, the Pixiebob because this breed is described as, ‘dog-like in their devotion and loyalty and are easily trained to walk on a leash’. You get a bonus: you can go for walks on a leash! But it won’t be as easy as you might think. Another breed described as dog-like is the Siberian.
Which cat breeds are lap cats?

Once again it is unwise to bracket breeds into those that like and dislike laps because whether a cat is a lap cat or not depends a lot on the individual cat’s temperament not the collective temperament of a cat breed.
That said, being forced into making a selection, I’d choose cats of the Siamese cat family by which I mean the Siamese, the Balinese (longhaired Siamese), and the short and longhaired Orientals. There are other breeds associated with the Siamese but these are the main ones who like warm and cosy laps and close contact with their human.
Gloria writes:
‘Nothing gives them more pleasure than to sit on their owner’s lap, sleep on their owner’s bed, and even share their owner’s pillow.
Siamese cats are said to be ‘loyal’ and want to be ‘as close as possible, and their closeness verges on the desperate’.
Which cat breeds can be left alone?

All domestic cats like the company of their good human guardians! Note the emphasis on the word ‘good’. I mean a person who loves their cat and gets love back. That’s the arrangement and why we like living with domestic cats.
It is unwise to try and select a cat breed which can be left alone because cats should not be left alone but, that said, I’d select the American Shorthair which is described by Gloria Stephens a cat expert and author of Legacy of the Cat as ‘a low maintenance cat. They are well adapted to apartment living. They ask for nothing, make no demands on your life, and give back love in return’. How about that?
P.S. The best way to adopt a cat is to visit your local rescue center and meet them. One might come up to you, sit on your lap and purr. Bingo. Job done.
P.P.S. These selections are not complete. They are based on sound assessment but there are alternatives.