Cross Join Without Table?

I have the following structure with remote select permissions; I cannot create temp tables or use stored procs:

tblEvent with event_pk, eventName
tblReg with reg_pk, event_fk, person_fk, organization_fk

I'm currently using a case statement to get counts for these categories:
case
when c.person_fk is Null and c.organization_fk is not null then 'Employer'
when c.person_fk is Not Null and c.organization_fk is null then 'Individual'
when c.person_fk is not Null and c.organization_fk is not null then 'Both'
else 'Unknown'
end

But I need some kind of count (0) for every category. I've used a cross-join, group by in the past - but what do you do if you don't have a table? For example, the end result when selecting event_pk=(112,113) would be:

event_pk, myCount, countCat
112 0 Employer
112 1 Individual
112 4 Both
112 0 Unknown
113 5 Employer
113 0 Individual
113 0 Both
113 2 Unknown

Thanks for any help,
jb