In my opinion, you should have more openings at north and east side of the the flat so you can get more morning sun light, but in flat no 4 east direction is completely blocked.
North East is the direction where you can have puja room but one of your WiW and adjacent toilet is coming there. Also, master bedroom in that direction is not suitable for the owner/Karta of the house. So, even if you purchase this flat, you should use the room in South West direction.
South east, which is agni corner, is being used for the entrance.