Styrofoam panels decorated with fabric can be attached directly to the ceiling. This is temporary and your plans to insulated outside and install a new roof will return the interior to normal. I am assuming the interior is finished and you do want it to remain as it looks as much as possible.
My parents did this in our old farm house in part for noise reduction. They used strips of wood paneling over the seams to create a "look" and to also provide structural support to hold the panels up. It actually worked decently and was up for probably 30 years. Nothing like a temporary fix to create permanence.
As an aside, the mice loved squeezing into the space between these panels and the ceiling and running around. This is the time of the year here that they little @#$ come into the house through my basement to escape the oncoming winter. I've found that they are attracted to sources of water like my sump and I leave poison out for them there
On BD H52, W50 T27, M26 S21, D23 BD-9-Mar-16 D-15-Jan-18 Final-19-Apr-18 I am a storyteller. The story may do you no good. But a story is never for the listener. It is always for the one who tells
