Did you properly clean the logic board before you started repairing it? If you don't do that, there would potentially still be water under the IC's and once you powered it up, it would have caused more damage.
Now regarding the PMIC did you test the output lines for shorts when the PMIC was removed? That many shorts is usually a PMIC problem but in this case you replaced it. You need to look at this one line at a time. Look at PP_CPU, PP_GPU etc. Take note of all the shorted lines. Let me know what you find.