This dedication to the act of harvesting lumber itself is condoned in the book through the main dramatic tension: the work of the Limberlost harvesters to make sure that no timber thieves illegally cut down trees and cut into their profits. Because the conflict focuses so closely on the legality of who should harvest the Limberlost, and not whether the harvesting itself is a good idea, there is no abject environmentalism to speak of in the text - just ownership of land and nature's resources. McLean even just primarily objects to them not taking lumber efficiently enough - "McLean was angry beyond measure at this attempt on his property, for in their haste to fell the tree the thieves had cut too high and wasted a foot and a half of valuable timber" (Chapter 7). If the book was more directly about stopping the harvesting of the Limberlost altogether, would that affect Freckles' personal journey in any way? How do you think it would change?
With regards to whether or not Freckles needs the missing hand in order to cement his lamented status, I think that it actually carries symbolic meaning that is vital to the novel's message. In the end, I do think that it would be possible to show a young man coming of age and learning to do for himself without having him be literally crippled, but the novel benefits from that missing hand offering a metaphorical disability. At the beginning of the novel, he must prove himself, as all young men have to prove themselves once going out on their own to make their way - the doubt that McLean expresses could also be in relation to his courage, experience, or discipline; however, I think the hand provides an important visual symbol for this story. It doesn't matter whether or not Freckles actually has a disability; Freckles clearly thinks he can manage without it. What matters is that McLean and the others see the disability, or at least the potential for one. Freckles' journey then becomes about making them see the able-bodied man he is, instead of the ineffective and ill-equipped boy they see.
I think there is most certainly something to be said about Angel's capability to lie; there is a slightly misogynistic message within Freckles that can be paired with the book's emphasis on male bonding to create a very homosocial subtext. The boys of the Limberlost all pal around and kid each other, and become very close; Freckles eventually feels as though he can trust them. On the other hand, Angel is proven to lie and deceive, with negative consequences. To that end, the reader could not be blamed for taking a very misogynistic message from the book.
Stratton-Porter, Gene. Freckles. Project Gutenberg. Web.