What is the legal pecking order of relatives to determine next of kin? If a single person with brothers, sisters, nephews, nieces, cousins etc makes a will and excludes those relatives, do they have any claim on the deceased person’s estate?
If you make a will it’s unlikely that any of the relatives you mention would have a claim on your estate other than in special circumstances, such as where one of them was receiving regular financial help from you and could prove dependency. There is an order of entitlement for people who die without making a will, but if you do make a will then the list and order of entitlement is irrelevant.