Stripping and cleaning a partially repaired deck

Due to a botched repair job by a relative last year, I'm about to replace a contiguous 1/4 of my deck with new boards.

I'm trying to determine the correct order of repairing/stripping/brightening to consolidate as much effort as possible.

I plan to strip and brighten the old wood. And clean and brighten the new wood.

If I repair first, will overspray from the stripper hurt the new wood or will cleaner from the new wood hurt the stripped wood?

If I strip first, does the brightener really need to be applied immediately as per the instructions, or can it wait until after I've repaired and cleaned the new wood so that
I can hit the whole deck at once?

Thanks,

Mike