The simple answer to your question is yes, the beneficiaries of a decedant's estate must be notified, and yes, the administrator of the estate must demonstrate that required notices were given.
The timeframe for the notification is when the probate estate is opened, and at various points afterward, including the closing of the estate. If a will is involved, the Kansas estate must be opened within six months of the decedent's death or the will is no longer effective.
However, it would appear from your question that non-probate assets (annuities, POD, and TOD) are involved. These assets do not go through probate, and there is no court reporting for these assets. Generally, the beneficiaries are required to notify the companies holding these assets of the passing of the decedent, and then request that the assets be given to the beneficiaries. If these companies (insurance companies or banks) find out about the decedent's death through non-beneficiaries, then they will usually inform the beneficiaries of the process to claim their money or assets.