Preheat a grill to medium high. Combine the hoisin sauce, ketchup, pickle brine and honey in a large bowl. Transfer half of the mixture to a separate large bowl; add the pork and marinate, 5 minutes.
Add the mayonnaise to the remaining hoisin sauce mixture and whisk until smooth. Add the broccoli slaw, scallions and chopped pickle; season with salt and toss to coat. Set aside.
Brush the grill grates with vegetable oil. Remove the pork from the marinade and grill until marked and cooked through, about 3 minutes per side; transfer to a cutting board. Toast the baguette on the grill, cut-side down, 1 to 2 minutes. Slice the pork into thick strips; divide among the baguette pieces and top with the slaw and sliced pickles. Serve with vegetable chips.