Let's solve each equation step by step:

1) 4(-4a + 5b - 3c) = -7(d - 8 + 6f) = -1
-16a + 20b - 12c = -7d + 56 - 42f
-16a + 20b - 12c = -7d - 42f + 56
-16a + 20b - 12c + 7d + 42f = 56

2) 2a(-3b + 0.2c - 5d) = -8(5/16 * -1/4y + 1/24z - 2.5)
-6ab + 0.4ac - 10ad = 0.3125y - 0.3333z + 20
-6ab + 0.4ac - 10ad - 0.3125y + 0.3333z = 20

3) -(7(7a + 6) + 25a) = 13(b - 5) + (12 - 3b)
-49a - 42 - 25a = 13b - 65 + 12 - 3b
-74a = 10b - 95
74a + 10b = 95

4) (12 - 3b) = 1.6(9a - 3b) - 1.5(4b - 6a)
12 - 3b = 14.4a - 4.8b - 6b + 9a
12 - 3b = 23.4a - 10.8b
3b + 10.8b = 23.4a - 12

5) We will now simplify the last equation you provided:
1.6(9a - 3b) - 1.5(4b - 6a) = 11.4a - 4.8b - 6b + 9a = 20.4a - 10.5b

Therefore, the system of equations is as follows:
-16a + 20b - 12c + 7d + 42f = 56
-6ab + 0.4ac - 10ad - 0.3125y + 0.3333z = 20
74a + 10b = 95
3b + 10.8b = 23.4a - 12
20.4a - 10.5b = x (x is the remaining unknown value)