I met with @Gaurang_Tandon today to discuss this further. Through his direction and some experimentation, the following was landed on:
First & Last Name: {formtext: name=name}
{note: preview=no; trim=yes; insert=no}
{parts=splitregex(trim(name),"^\w+(\W+)")}
{lastname=parts[count(parts)]; trim=yes}
{chars=lower(substring(replaceregex(lastname, "\s", ""), 1, 3))}
{if: comparestrings(chars, "duf")<=0; trim=left}
{assignee="Armand Izzo"; trim=left}
{elseif: comparestrings(chars, "lai")<=0; trim=left}
{assignee="Reggis Metayer"; trim=left}
{elseif: comparestrings(chars, "rev")<=0; trim=left}
{assignee="Dahly Jimenez"; trim=left}
{elseif: comparestrings(chars, "z")<=0; trim=left}
{assignee="Eleida Sanchez"; trim=left}
{endif: trim=left}
{endnote}
Full Name: {=name}
Last name: {=lastname}
Assignee: {=assignee}