I always wear shorts in the summer (can't stand heat). However, I just bought my first pair of linen pants & wore them yesterday. But for everyday, casual daytime stuff in hot weather, I'll stick with my shorts.
2) Will try boat shoes, but honestly in California I've only seen it a few times, and never loafers.
Where do you live? All around the Bay, SF, Marin/Tiburon, most of SoCal people wear boat shoes / loafers without socks all the time. And if it's not boat shoes or loafers its drivers or white/pastel canvas shoes with low cut socks.
I think it is like so many other things, are you in the company of your peers? I work for a fairly large company of 12,000 plus employees and it an extremely casual work environment. People rarely wear a SC or Suit and usually it is a bad fit and the tie/color combinations just looks bad. Anyway, back to shorts, a lot of people wear shorts and tee shirts. I have worn shorts for 15+ years for 6 months of the year but I have always worn nicely pressed shorts with polo shirts, and I out dress 90% of my peers. No one cares if someone has hairy legs or not because so many people wear shorts. I usually wear tennis shoes because shoes with no socks don't suit me especially because of my golfer tan and sweaty feet. In fact, I live in a SW city where it is acceptable to go to almost any restaurant in shorts. I think it all depends on what others around you are wearing and in what you feel comfortable. I don't subscribe to "rules' of fashion (might get banned from SF for this comment). I wear what I feel is appropriate based on the situation, and what I feel comfortable in and like.