Trying, but hard.

So far the ones we're sure of are:

[6/F] = Cabal/ DS Structure

[9/I] = War/ Conflict/

[10/J] = No. 10 Downing Street/ British Government/ Prime Minister/ Umbrella Organization

[19/S] = FBI/ FBI assets

Less sure of, just guessing:

[13/M] Q referenced with the Epstein Temple. Cult?

[3/C] Something to do with CIA organization.

[5] Spyders. CIA assets? Contractors. Spies?

They seem to also be targets because they are set in kill boxes [ ].

The clue for Marker [1] is a Trump tweet on 3/15 (Ides of March) that mentions Bill Barr and the southern border wall. Struggling on that one.