The labelled backpacks are meant for reducing clutter in the car, no further secrets behind those.
I haven't had any problems with the merc agent, they spawn at one of the entry points and then walk to the hotel. The agent then takes some time off, depending on how expensive that merc was.
A propos expensive, I'm not having any problems with the money in BSM. There's a free and pretty good merc you can get right away by going to Santa Maria. Solve his quest either way and there you go, won't need Benicia except for muling duties
