Bringing money in

You will have to apply in Brazil for CRMN. Since 2017. MJ (PF) handles such.
Anything 10 Mil and over just needs to be declared

Since the 2017 immigration law reforms,  the Brazilian Foreign Ministry no longer issues permanent residency visas.  Your husband will be applying for a VITEM XI visa, a temporary family reunion visa that will allow him to apply for permanent residency with the Federal Police when you arrive.  Be sure to have duplicates of the documents he presents for his visa, because you'll need them for the Federal Police, as well.  Check "Imigração" on the Federal Police website for other requirements.
As Tex says, there's no set limit on the amount of money you can bring in, you just have to declare it if it's over a certain amount.   Debit cards from your British bank should work in Brazilian ATMs, so you won't be without a source of cash. 
Your husband will have to wait to have his permanent residency approved to open an account at a Brazilian bank, but you, as a Brazilian citizen, can open one immediately.   Doing this and transferring funds from your UK account is a much safer way to move larger amounts of money than are required for daily cash needs.