EDIT

This is the statement to get all nomenclatural status changes for update and create and which are changed to nom. illeg.:

select distinct name.fullTitleCache, def.titleCache 
from NomenclaturalStatus_AUD ns join AuditEvent a on a.revisionNumber = ns.REV 
join TaxonName_NomenclaturalStatus t_ns on t_ns.status_id = ns.id 
join TaxonName name on name.id = t_ns.TaxonName_id 
join DefinedTermBase def on def.id = ns.type_id 
where a.date > '2018-06-01' and (ns.revtype = 0  or ns.revtype = 1) and def.uuid like 'b7c544cf-a375-4145-9d3e-4b97f3f18108'

select distinct name.id nameId, name.fullTitleCache fullTitle, defNow.titleCache currentStatus, a.date, ns.revtype
from NomenclaturalStatus_AUD ns 
join AuditEvent a on a.revisionNumber = ns.REV
join TaxonName_NomenclaturalStatus t_ns on t_ns.status_id = ns.id
join TaxonName name on name.id = t_ns.TaxonName_id
join DefinedTermBase def on def.id = ns.type_id
left join TaxonName_NomenclaturalStatus MNnow on name.id = MNnow.TaxonName_id
left Join NomenclaturalStatus nsNow ON nsNow.id = MNnow.status_id
left join DefinedTermBase defNow on defNow.id = nsNow.type_id
where a.date > '2018-06-20' and (ns.revtype IN (0, 1)) and def.uuid like 'b7c544cf-a375-4145-9d3e-4b97f3f18108'
ORDER BY name.fullTitleCache, a.date

to remove duplicates remove a.date from select and order by

yes you are right, it is better to create a new status with default type nom. illeg. then we do not have to set the selection for the combo box.