First, I would not necessarily draw any conclusions from a sample of unfermented wort or unconditioned beer. The "green" beer rarely has the same taste, complexity, etc. I get after patiently letting the beer condition. Some flavors are metabolized by the yeast or otherwise go away during conditioning, while other flavors are able to then come out (or develop). Nevertheless, I find it useful to sample green beer as a learning experience.
The concentrated wort will not necessarily be more bitter (but it may be). Perception of bitterness varies based on a lot of factors, not merely the number of IBUs, or concentration of alpha acids and other bittering compounds. One of the major factors is residual sweetness from unfermented sugars. When you concentrate your wort, you concentrate both the hop compounds and the unfermented sugars -- I am not sure how that will affect your perception of bitterness (how the balance will go).
Second, you may not want to transfer the beer at all to a secondary fermenter. You can find threads on this forum debating that point, but in short the tradeoff is between risk of oxidizing your beer or introducing contaminants vs. limited to no benefits in terms of getting the beer off of the yeast cake and perhaps aiding in clarity. I would advise a new homebrewer to avoid secondary because your lack of practice in transfer and sanitation technique makes the bad risks more likely.
Third, temperature for "secondary fermentation" (or continued conditioning in the primary fermenter) is not dependent on whether you transfer to a fermenter. It depends on your style of beer, yeast, etc. For a pale ale, I would try to stay at 60-65°F, but it depends a bit on your yeast strain. 42°F seems like a lagering temp to me, and it is likely to put your yeast to sleep, rather than have them actively continue to work on the beer.
Fourth, as far as "building" malt or body, all the malt or body you were going to have was there at the end of the boil. But maltier flavors and perception of body may come to the fore after conditioning.
Finally, as far as dry hopping, it is a matter of personal preference. I would lay off of it, given that it seems like a high ratio of IBUs to gravity and you already say it is very hoppy.
BTW, I am concerned that your fermentation is not complete if you finished at 1.017. What yeast did you use?