To answer the first question:
can I make a profit by salvaging items for their components, then using said components to smith my own items?
You can. Early in the game, you can't really make enough profit doing this to make it worth the trouble (unless you are just super OCD about wringing every little bit of gold out of every transaction), but eventually--especially once you max out your Blacksmithing--it seems the items you can craft can be worth a fair bit more than the originals that you salvage. Here are the results of a quick and dirty test I just did comparing prices of a looted Fine Azurite Greatsword --> Mastercrafted Azurite Greatsword and a looted Crude Sylvanite Greatsword --> Mastercrafted Sylvanite Greatsword. Note that I'm level 22 with maxed Blacksmithing skill and 1 point in Mercantile.
First let's start with some base numbers--sale prices of the original items and the base components in play:
Fine Azurite GS: 810
Crude Sylvanite GS: 1272
Large Az Blade: 215
Large Sy Blade: 411
Crude Hilt: 59
Basic Grip: 59
Simple Bindings: 59
For the Fine Azurite Greatsword, I salvaged and reloaded until I got the Primary and Secondary components needed to craft a new sword--the blade and the hilt. It took 16 salvage attempts to get both, but 4 of those times I got the blade and an optional component (simple bindings or basic grip), and 1 time I got the blade plus both optional components.
For the Crude Sylvanite Greatsword, on my second salvage attempt I got the Large Sylvanite Blade, the hilt, and bindings. Good enough for me.
Because my Blacksmithing is maxed, all items I craft are "Mastercrafted" items, which means they get an additional effect that varies depending on the type of item. Azurite Greatswords seem to get +3% Damage, and Sylvanite Greatswords get +6% Damage. It appears that Mastercrafted items are always at least green, even if you just use two components (Primary and Secondary) to craft them.
I compared prices I could fetch for both types of swords when I used just 2 components, then 3 components, then all 4 (I never attempted adding a gem). All components except the blades were the most basic possible (crude hilt, simple bindings, and basic grip). Here are the results:
Mastercrafted Azurite GS (original sale price of Fine AGS: 810)
2 components: 1034
3 components: 1110
4 components: 1186
Mastercrafted Sylvanite GS (original sale price of Crude SGS: 1272)
2 components: 2407
3 components: 2581
4 components: 2755
What's interesting is that the effects of the additional components on the sale price seem to multiply it by a factor of ~1.07 with each addition rather than simply adding the value of the base components. So it seems like it might be worth it to salvage lots of the junk you get early in the game just to get the basic secondary/optional components to keep and use later on to pimp out stuff you craft for sale--especially considering that, e.g., the crappy iron gear is worth < 100 gold early in the game, but the parts you salvage can increase the worth of Sylvanite and Prismere gear (I'm guessing) by much more than that. Also, I should note that the 2 optional components for greatswords both have the same effect--+5 health. It's likely that value of the crafted item is calculated based on the stats of the crafted item rather than the value of the components that go into the item, so using different components will certainly give you different final values. I just used the basic components so as not to introduce too many variables.
Now--I wish, for this test, that I'd had a Crude Azurite Greatsword and a Fine Sylvanite Greatsword to compare as well just to see for sure how much difference in the original sale price Crude vs. Fine makes and if the difference becomes more, less, or equally pronounced with higher quality raw materials. Obviously salvaging Crude and Fine gives you a chance to salvage the exact same components--the only difference is the stats/price of the original items (so you make a bigger profit off salvaging Crude items as compared to Fine).