Its very very easy to retaliate to his nasty ways however, you are two people that have only recently split and it will be nasty for a bit but may calm down (although I expect you'll still get shit behaviour). I wouldn't report the mortgage fraud because it will bite you in the arse one day and it is just more ammunition for him to throw at you.
Ignore his texts, only communicate via email about your DD and do not retaliate to anything he or his parents say. Keep your head and your dignity held high. You will only continue to be abused if you take on board what he is saying.
Do not do anything that they can use against you i.e. stopping contact, changing locks etc As long as he is bringing your DD back on time then let him have access anything else and you will be seen as obstructive and that won't go down in court well.
Document everything with time, place etc. Times you have offered contact and he has refused. Send him an email of proposed contact times and asking that you both be respectful of each other and do not argue in front of daughter. use a contact diary so that you can write anything down that needs to be said about DD e.g. what she has liked playing with, whether she has been poorly etc. Ask him to write any concerns or any new things daughter has achieved in it. If he refuses, still carry on doing this as this will make you look better in court.
Always, always be there better person and the one allowing contact and good shared parenting. Do not get swept away with his nasty behaviour and lower yourself to his level.
He is the one that has to live with himself about treating you and his daughter this way and at some point in the future he will realise what he has done. He and his family are pretty much out of your life once you move and you will only need to contact them concerning DD. Give him your bank details, he has said he wants them so give them to him he needs your sort code and bank account number. Not giving him these makes you look obstructive because he can now prove via text that he has asked for them but instead of just giving them to him you haven't.
DISENGAGE DISENGAGE DISENGAGE
P.s. this is form speaking from experience but he way I retaliated to every lie, every bit of shite behaviour and it really wasn't worth it just made people think I was the looney and unreasonable person he was saying I was. Stay strong and ignore him and his lies.