Hi, Sam-
Re. DF (degree of freedom) counting: yes, you are correct. Adding a regressor to a general linear model means using up one degree of freedom. Censoring can be done (as you note) by including a column of all zeros except for a 1 at the time point to be censored-- hence, censoring using 1 DF. Interestingly to bandpass a given frequency, you have to include *both* a sin() and cos() form of it in the model, so that uses up 2 DFs. That is part of the reason why bandpassing is so expensive, in terms of DFs. And indeed, bandpassing won't zero-out a time point (but you might see some apparent 'ringing' effects).
(To your point on a paper-- there is one in progress. It has taken a while to progress, because of so many topics involved, but slowly, slowly...)
--pt