Tier 2 ILR query

Hi I just needed to ask if someone’s ILR is refused after spending 5 years in the UK on tier 2 visa, can they apply for ILR after spending another 5 years (after spending the cooling off period)? Can they start working on tier 2 visa again from the start?
Also if someone has a break in continuous residence(due to abscences exceeding 180 day limit) during the second year on tier 2 visa and they spend the remaining three years without any break, will they be given an extra year to complete those missed/absent days when they apply for ILR after total 5 years? As I understand tier 2 can be extended for 6 years?

Can tier 2 visa be extended beyond 5 years?