Re: 9.3.5 update
iOS updates are what are referred to as cumulative updates. In other words, any and all iOS updates contain the fixes for that version (in this case 9.3.5) and any and all fixes that were included in any past versions as well.
For instance, if you had iOS 9.3.0 and you update to iOS 9.3.5, the update package you get will contain the fixes that are included as part of version 9.3.5 but also the fixes that were included in 9.3.1, 9.3.2, 9.3.3, and 9.3.4. Hence the reason why they call them cumulative updates.
Think of cumulative updates as a rollup of several hotfixes and patches all rolled up into one downloadable and installable package. One shot, one patch, one download and you're done.