Yes even the black tank valve would have been caught/corrected during a proper pdi. They pressurize the entire fresh water system and verify no leaks. Obviously drains aren't pressurized, I don't know the procedure but it sounds like quite a leak under the sink, I'll say that may/may not have been caught during pdi. All the screws and loose parts should have been caught.
In fact, the RV dealer often sublets delivery to a privately owned trailer transport company that tows every trailer from manufacturer to dealer. Before they tow, transporter walks through and make detailed list of problems. I've seen these list before, and they are so specific, they check them over pretty close because they don't want to be blamed for anything broken. When it arrives at dealer, dealer walks through and anything dealer finds loose/broken/damaged is either transporter fault or manufacturer defect. Like checking in a ups package.
I don't know why there are so many problems with yours but there are many checks in place from manufacturers, transporters, dealers, then customers. I know things get missed by us customers because we are inexperienced at looking for these suddle problems. But it is our responsibility, and if we fail, i don't know that a manufacturer will just deliver you another. The dealer should make you high priority and fix it all for you. Don't miss anything this second time. Spend some serious time checking everything to make sure it is correct.
I am curious, just curious who manufactured this trailer and what model is it?
