questions
If he had still lived out on Little Bitch road, site of the old Verdreaux home place, Sam would have burned to a crisp (as Marta Edmunds did) in the minutes after the initial explosion. But the home place and the woodlots which had once surrounded it had been taken for unpaid taxes long since (and purchased back in ’08 by one of several Jim Rennie dummy corporations … at bargain-basement rates). His baby sis owned a little patch of land out on God Creek, however,and that was where Sam was residing on the day the world blew up. The shack wasn’t much,and he had to do his business in an outhouse (the only running water was supplied by an old handpump in the kitchen), but by gorry the taxes were paid, little sis saw to that … and he had THE MEDICAL.Question 1: Does “home place” in this case mean “house” or “homestead”?

Question 2: I think “Sam would have burned to a crisp” is a typo. It is supposed to be “Sam would have been burned to a crisp”. Right?

Question 3: Does “the home place and the woodlots which had once surrounded it had been taken for unpaid taxes” mean “the home place and the woodlots which had once surrounded it had been confiscated because of unpaid taxes”?

Question 4: “dummy corporation”== “fake corporation” == “non-existent corporation”?

Question 5: Does “The shack wasn’t much,and he had to do his business in an outhouse” mean that “The shack was too small to have an inside toilet so Sam had to empty his bowels in an outhouse”?

Question 6: by gorry == by God? He had THE MEDICAL because the taxes had been paid? Does “saw to that” mean “paid off the taxes for him”?

P.S. What kinds of taxes does “the unpaid taxes” refer to?

Question

questions
If he had still lived out on Little Bitch road, site of the old Verdreaux home place, Sam would have burned to a crisp (as Marta Edmunds did) in the minutes after the initial explosion. But the home place and the woodlots which had once surrounded it had been taken for unpaid taxes long since (and purchased back in ’08 by one of several Jim Rennie dummy corporations … at bargain-basement rates). His baby sis owned a little patch of land out on God Creek, however,and that was where Sam was residing on the day the world blew up. The shack wasn’t much,and he had to do his business in an outhouse (the only running water was supplied by an old handpump in the kitchen), but by gorry the taxes were paid, little sis saw to that … and he had THE MEDICAL.Question 1: Does “home place” in this case mean “house” or “homestead”?

Question 2: I think “Sam would have burned to a crisp” is a typo. It is supposed to be “Sam would have been burned to a crisp”. Right?

Question 3: Does “the home place and the woodlots which had once surrounded  it had been taken for unpaid taxes” mean “the home place and the woodlots which had once surrounded it had been confiscated because of unpaid taxes”?

Question 4: “dummy corporation”== “fake corporation” == “non-existent corporation”?

Question 5: Does “The shack wasn’t much,and he had to do his business in an outhouse” mean that “The shack was too small to have an inside toilet so Sam had to empty his bowels in an outhouse”?

Question 6: by gorry == by God? He had THE MEDICAL because the taxes had been paid? Does “saw to that” mean “paid off the taxes for him”?

P.S. What kinds of taxes does “the unpaid taxes” refer to?

Answer

1. "home place" is not a standard expression. It appears to refer to the house and the property it sits on, since it is subject to legal proceedings

2. “Sam would have burned to a crisp” is a correct, as is “Sam would have been burned to a crisp”. It is a style difference. I can say "The paper was burned", or "The paper burned". Burn can be transitive or intransitive. 
In this case "Same would have burned" is describing Sam doing the act of burning, rather than something burning him. Like I said, it is really just a style difference - little difference in meaning.

3. Yes. "for in this case means "in place of" or "in lieu of" - For example, "If you cannot pay back the $100 you owe me, I will accept your watch for the repayment"

4.No. A "dummy corporation" refers to a corporation that exists only to own something. For example I can register 10 companies - I may not even name them but just use the standard number the government supplies. These companies might never do anything but own something for me. In some cases this is a good way to organize large holdings, and separate them legally in case there is a problem. Often people use them for illegal reasons also - to make it harder to trace wealth.

5. Yes. An outhouse is a tiny shed over a hole in the ground for that purpose.

6. Gorry is slang for God - I think only in England - certainly not in North American English, where it means nothing
"saw to it" means "made sure" - she may have done it herself or found another way, but she made sure it happened.

THE MEDICAL is in capitals - I think it may refer to a significant event in the story, involving a medical exam - it is a change of topic

"unpaid taxes" refers to taxes you were required to pay to the government, but have not paid yet and are late paying