Migration notice received

gerrys6

I’ve started the to do list and have nearly completed that part once I click on the box at the bottom does my claim start from then as I still have another two payments ya before I want to migrate fully ?
also as I am on full pip my grown kids don’t have to pay rent or council tax nor do I will that still be the case when I migrate ? And will i only be given a percentage of my rent or will I get the full monthly /weekly rent paid to me? Also if I leave it till the last minute to tick the box and fully apply if there’s any hiccups will it delay all the migration. I e the rent dilemma or anything else I don’t want to end up in debt for rent as I don’t ever have rent arrears.