Stress to your landlord that you are unsafe in your apartment. Put it in writing and hand it to the apartment manager first thing in the morning and get a signed receipt for the notice. Ask for a change of locks at that time. The apartment owners will not want a liability claim if you are assaulted on their property once you have proof of applying for help.
If you have given notice let them know of the waiting period til mid-late November for a pet accepting apartment.
You did not say, but were you living in these apartments when he broke the chainlock? If so they should have been made aware of the damage then and that is evidence for your concern.
Anyone who is a “mutual friend” and buying his claim that he would not harm you is either not your friend or an ostrich. You need someone on your side in any meetings. Call on Instinct or someone else nearby who is exclusively your friend to be present at any meetings.
There is a major difference in keeping it friendly and keeping it civil.
Remember you would be safer with your cats living in your car than in a place he can waltz in at any time.
Now is not the time to make nice. You don’t have to be a threat but you need to attend to your safety. Locks, alarms and exclusive representatives of your side.
Box his stuff and put it in the apartment storage and tell him everything is there and not in the apartment so you don’t want him there for any reason.
If you have not done so, contact legal aide and/or a women’s shelter for help filing against him and get the ball rolling.