Sinmo

My 2015 Sienna LE has only 65K miles, and has had no problem since Day 1. Stock Battery was going dead (Due to extended TELEWORK from home), so I replaced it recently. Also, installed Front/Rear Dash Camera last SAT, and tested it while running 30 minutes. Then, I shut off motor. Two hours later, I tried to start to go somewhere. It cranks strongly, but won't start. Got above DTC via OBD II Reader. P0351~P0356 refer to Ignition Coil Primary/Secondary Unit, while P1604 is Startability Mul-function. Tested all fuses & relays, and all OK. Did spark test at coil connection for 2, 4, 6 cylinders on the front, but found no spark while cranking. Tested EFI connection with NOID light, no light comes on while cranking. Fuel pump makes humming noise, so I think it's OK. I can't understand all 6 coils going bad at once without any warning. Do it be that one Coil going bad gives you entire 6 cylinder coil fault code? I hate the idea of taking entire Manifold & Throttle Control Unit just to get to 1, 3, 5 coils/plugs in the back (4~5 hour DIY job) Think it's more electrical/wiring/ECM issue? Does anyone has any idea/suggestion on this issue before I embark on 6 Coils & Spark Plug change?? Thanks in advance.