Advice needed - Recourse to public funds/Benefits

[Masquerade]

Hello, new to the board and I hope you can help.

My Mexican fiancée is currently applying for a fiancée Visa. Upon the issue of that Visa she will join me to live in UK where we will get married within the 6 months allocated to do so by the Visa. I am a British citizen with no restrictions on my rights to live here.

I am currently in receipt of various benefits:
Employment & Support Allowance (including Support group component and enhanced and severe disability premiums). The award appears to be part contribution based and part income related.
Disability living Allowance – low rate mobility and medium rate care
Local Council Tax – I get single person discount and council tax support

I live alone in a house I own outright.

My query relates to how my benefits are impacted when my fiancée comes to live with me and more importantly how we ensure her application and stay will meet issues of being "no recourse to public funds" as will be a condition for Visa. The rules seem incredibly complex and reading some old entries on this forum makes it seem even more so.

Do I change my claim for Employment & Support Allowance into a joint claim and insist they do not pay any additional monies (i.e. continue to pay the single person rate)? I presume I will lose severe disability premium as no longer will be single.

For Council Tax I see some old entries on the board regarding an anomaly of the law which arises when single person discount is lost and thus technically greater amount of council tax support could apply. I note a moderator of the board suggested this was receiving some parliamentary interest back in 2014. What is the situation and what should I do... both with regard to addressing the matter in the Visa application and in terms of actually thereafter (assuming Visa granted) dealing with the details of my claim with local authority.

I should add that regarding the maintenance test applied for the Visa given I am a recipient of DLA we should pass without difficulty and thus do not see this as an issue.

Thanks in advance for any advice.