I am an electrician.
eh? that means the original installation was not up to code. You are supposed to pigtail each outlet to prevent the problem of one bad outlet taking out the chain.
not true. its only on Multiwire branch circuits that you must pigtail for the reasons greenman stated. we do mostly commercial and industrial and run into MWBC a lot.
Grounds are always pigtailed, there is no provision for 2 ground connections on a receptacle. double lugging is not allowed unless the thing is UL listed for it. plus the code section in 250 mentioned above. you can dais chain though, and we often do, bare ground starts at the metal box, hits both recepts in a quad and then gets wire nutted to the ground from the branch circ.
pigtailing or not is not the cause of an outlet going bad. back stab connections, loose connections, etc. are. depending on the install we will pigtail or not. all our 20 amp stuff gets pigtailed in industrial, and we do or don't depending on the box size, the outlet type and how many wires are in a box in other use cases. is it "better" sure, but totally unnecessary in most situations. a wire weather pigtail or not improperly fastened is a hazard.
yes, get that FPE stuff out of your house ASAP. 2400 is not too bad a price for that work. we would charge more.