Changing to Period 8 house

Dear Master Cecil,
I live in a 2 storey terrace link house. My house is facing southeast 2 (main road) but my main door at the side which is facing northeast 2, I have the following doubts:-
a. My main door is facing a wall sharing with my neighbour which is 7" apart, will this obstruct the chi coming in? By doing this, I can avoid our car to be drived towards our main door.
b. My main door is still located in southeast sector even though it faces northeast. May I place a water features directly in front of the door (7" apart) to indirectly activate the water star #8 (resides in southeast sector in period 8)
c. I was told that in order to change my house from period 7 to period 8 house, I have to change part of the roof tiles, floor tiles and main door. My questions are:-
(i) Can I just change 10% - 20% of the entire roof tiles?
(ii) Do I need to change the ceiling board as well?
(iii) Can I not to change the ceiling board and just let the sunlight shines to the floors through an existing openings?
(iv) I will lay tiles on some of the cement floors, will this considered as changing the earth chi?
(v) Is it changing the main door into a brand new door will be alright?
d. When I impose the eight mansion chart/flying star chart, whether my car porch, verandah & backyard to be part of my house if it is attached to my house and with roof tops.
Thanks & Regards,
Fiona