Do you want to re-draw attached pdf's in Autocad or are you going to send new design draft? For the pipping plans, I suggest pipping spool drawings (isometric) since that is the best way yo interpret and manufacture. Electrical design no problem.
I’m an Electro-Mechanical Engineer with lots of experience in design in 2d AutoCAD (Plant views, building services, HVAC, Fire protection, pipping, etc.), 3D drawing in AutoCAD including projections/manufacturing plans, Assembly plans, part list, pipping spool, isometric etc. I also work with Siemens Solid Edge, or solidworks. Extensive experience with international standards (ASME, ANSI, DYN EN, etc).