I think the answer to 1a is 20N * 3m (3m is the initial height of the block)
For 1b, I'm guessing the work by the normal force is just the work done to move the block horizontally. I don't feel like doing the math, but calculate the horizontal component of the normal force (its just trigonometry I think) and multiply it by 4m (the block moves 4m left)
I'm not sure why your answer for 1c is wrong. That seems totally right to me.
For 1d, you could do gravitational energy at beginning - energy lost by friction = kinetic energy at bottom of plane + gravitational energy at end
so you'd end up with 20N*3m - answer to 1c = kinetic energy at bottom of plane + 0
For 1e, do [answer from 1d] = 1/2 * m * v^2 and solve for v (you can get the block's mass if you assume this is on earth and g = 9.8m/s^2)
For 2, you can use conservation of energy (all the kinetic energy is converted to spring potential energy, the spring potential equation is 1/2 * k * x^2)
For 3, I'm assuming the spring is going to distribute the same amount of energy to both blocks. You can just set the kinetic energies of both blocks equal to eachother and solve for the speed of the 7kg one. Then you can add the two kinetic energies to answer 3b
