Hello, I am Keith, one of the experts on Just Answer, and happy to help you with your question.
DLA [now Personal Independenc Payment] is a non means tested benefit so becoming directors of a business will make no difference to these benefits.
In general terms family tax credit and council tax benefit are means tested. Thus the effect on these will depend on the sum in directors' fees paid out by the company or drawn from the company, if any. If no fees are drawn then these benefits will not be affected. Council tax benefit is operated by individual councils under their own rules.
I do hope that I have shed some light on your position.
A limited company makes annual returns to the Registrar of Companies and files Accounts and Corporation Tax returns annually on line. If it pays directors' fees these must be done through PAYE arrangements. If profits are retained in the company they will be subject to Corporation Tax at 20%.
Normally one would buy an off the shelf company from one of the many company formation bureaux.
Thank you for your support.