HELP! on Repairs -OEM or Aftermarket - have diagnostic

got couple things gone wrong with my car so went and got a diagnostic which is attached...

i got bad front lower control arm bushings.. tiny leaks in valve cover gasket n power steering n a squeaking a/c belt idler pulley

the valve cover gasket seems pretty easy DIY so am knock that off

power steering is just a small leak and put some lucas oil stop leak n seems to be working as my check engine light has turned off.

the bushings should i go OEM or aftermarket ?

the pulley just squeaks at the moment, was wondering should i jus replace whole set or just the a/c idler pulley n if whole set OEM or aftermarket

think i can knock off the bushings myself but idk about the pulleys should i take it somewhere or look for a DIY

oh and on the last page what the heck is "rear axle or driveshaft diagnosis rear diff bushing" and why does it cost almost $1,000

so any help would be great .. links are also good