1. Did you ask the other LBS why they advised you not to take your road bike out on the local trails? They probably know more about the condition of those trails, and know more about your bikes and the tires that are on your bikes and thus be able to give you more informed advice than those of us sitting at our computers. Is the gravel on those trails loose in places, or, does it get muddy? In general, the wider width and more pronounced tread on your hybrid tires might be more suitable for that kind of terrain than tires on your road bike, which, without knowing what they are, I am guessing might be substantially narrower and have much less tread and which might be more prone to flats on that kind of terrain. You can in theory change the tires on your road bike to fatter tires with more tread, but you have to ask yourself if that is worth the hassle. You might not go all that much faster on the pulverized gravel/compact dirt than you do on your hybrid anyhow.

2. i honestly don't know why they call them clipless - it's one of life's little mysteries - but I'll take a stab at it, and if anyone cares to correct me feel free. You may have noticed that some pedals have what some people call "toe clips", sometimes called "cages". Those are the old-fashioned way to affix your foot to the pedal. Some people even still use them to this day (including my husband the retro grouch). Once upon a time, toe clips were the ultimate in pedal design technology. Then at some point some genius came up with a system which attached the pedal directly to the bottom of the shoe using a clamping mechanism. The genius yells out , "look, no toe clips!" and the onlookers gasp "wow, no clips!" and "gee whiz, look at him, he's riding clipless!", and there the term clipless was born. People nowadays confuse matters when they talk about clipping in and clipping out of their clipless pedals, its just one of those things.