Legal Question in Wills and Trusts in Illinois

In Illinois, your executor and successor executor are not required to sign your will, living will, or healthcare POA.

You are not required to have the signatures of those people. The power of attorney forms may contain a space for sample signatures, but that is optional and I usually avoid using it for the very reason you cite (it is unlikely that everyone can be gathered to sign at once and doing it separately is more likely to create issues than solve anything).

That said, if you are doing this on your own, I highly discourage it. Of all the wills I have seen that were prepared by non-attorneys, including the ones touted by online sites or software manufacturers, not a single one was entirely correct. Several, would not have been admitted to probate. Those that would have been would have resulted in the distributions being different than the drafter would have intended. In one case, it worked out, but only because the section with errors was irrelevant.