Are they related?
One is a brown classic tabby. He has possibly a bengal among his far away ancestors. These swivrls seems to also be rests of the renown bengal rosettes.
So the theoretic Ancestry is not nearer than a granddad, but probably even further back.
The other is a brown broken mackerel tabby; possibly he can be counted as a brown spotted tabby.
Its sometimes difficult to see in moggies the exact difference between these two.
In purebreds its usually easier to see, because these are bred for good spots. Pedigreed cats with unclear spots arent bred on, unless there are other important factors you want to use them in the breeding programme.