First of all, after reading their list I lol’d. Then I thought about it and lmfao.
I give you my play by play for the list. But first so I don’t forget, you said you pick up a new gas cap. FWIW most non-OEM gas caps are crap. I hate stealerships but you need a factory gas cap IMO.
Power steering – replace as much of the fluid as you can, and add in some power steering leak stop.
Tranny mount = eric covered that
Struts – if it rides OK and your not getting crazy tire wear, you can wait to replace.
Muffler – its leaking a bit, big deal.
Rear caliper slides – clean and lube? Wtf? I’d slap the mechanic. Total BS.
When the rear brakes need replacing, then you lube the slide. Doing earlier it totally unnecessary.
Valve cover gasket – try tightening the valve cover it first. Check all the bolts for tension, and tightening one flat at a time. Just don’t monkey it down you could make the leak worse.
Radiator hoses – if they aren’t leaking your fine for now. Replace them yourself if you want, they are easily replaced.
Oil leak – yup, 12 year old cars tend to leak a bit.
Tire – well if you need them, they are a wear item no getting around it