I think definitely keep the booking and makeover it's written somehwere that you absolutely expect every si glen person who has booked to be there, come what may.
I agree with going ahead. Also could say you really want everyone there come what may, but don’t make it seem a hard obligation. Everyone reacts differently to a death and there may be someone who just can’t face it just that day/week, but feel worse whatever they do. Attend and feel horrendous or go against the wishes of a close relative that has died.