How do I distribute my estate equally amongst a group of (unspecified) people? (e.g. to all my children)
By default, you should key all of the beneficiaries and allocate them a percentage. The system allows you to key in up to 2 decimal places, giving a maximum difference of 0.01% even if the assets are split between an "awkward number" of beneficiaries (e.g. 100% split between 3 beneficiaries). Ultimately, there will always be some rounding off when the estate is distributed.
Listing using broad categories can have serious downsides as they may still be ambiguous, overlap with other categories, and is often more prone to mistakes. Listing each personnel individually is still the preferred approach as it adds clarity, makes future updates easier, and helps prevent unintentional errors.
Similarly, both CPF and insurance nominations are not made to unspecified groups of people, rather you will need to list them down individually.
Regardless, if you wish to distribute your estate equally amongst a group of (unspecified) people (e.g. your children, nieces and nephews, siblings, etc.); in the Allocate Assets page, under Allocate Residual Assets, select "+ add a new person" and key in the following:
Full Name
Be distributed EQUALLY amongst {group}
Relationship
Others
Allocate the percentage accordingly.