ssuresh316...I hope all the pros on Houzz are in agreement here. Your room can be built as you envision it but we pros leave those sort of questions to a different kind of pro. Joanne is correct in that you need an engineer...but call a structural engineer. Civil engineers do roads, drainage, utilities and surveying. Structural engineers tell us how to make the building stand up.

I agree with divadeva. More lights. If you can add pot lights do it. If they're already there add task lighting and up the wattage on the bulbs on the pot lights (replace with LED and you can make them brighter because the wattage on LED is lower for brighter light). If you have all of that add decorative lighting. If ventilation is an issue find a way to move the air around or add air filtration. Maybe the HVAC is deficient. Maybe you can add a HEPA filter instead of the standard one that comes with the unit. Call an HVAC specialist to see if there is a way to boost air flow in the room.

I suggest you follow the step-by-step guide for creating storage cabinets under the bathroom sink. Take proper measurements - Measure the available available space in height, width and height. Cut Plywood to size - With a circular saw and framing square, cut all the required pieces out. You can use a sliding compound saw as an alternative. Attach the base and sides - Start assembling the sink cabinets by placing the bottom piece of plywood sheet on a flat surface. Attach the back and top boards - Place the plywood sheet for the top part of the cabinet and attach wood screws to connect it to both the sides. Turn the back faces of the cabinet upwards. Keep the back piece over the structure and fix it into place with wood screws. Attach shelves - Place the cabinet in an upright position to install the shelves. Slide a shelf into the structure so it is flush against the back. Attach door - Keep both hinges of the door on the same side of the plywood sheet. Drill them using wood screws into place. Now keep the door over the cabinet structure, extend the hinges to one of the side panels and fix them to make them secure. Fix a hasp closure on the other side of the door, placing it in the center of the hinges.

What is the dimension of your bathroom? Looks like 4 feet wide, can't make out on length though. Glass partition or tiles partition for shower would help to keep your bathroom clean and dry and revamp look drastically. Wall hung WC is must, again from cleaning and look perspective. If window is not providing any light ( though your photo suggests some light coming from window) this area can also be used for multipurpose. You are welcome for more queries. Tiles selection can be decided based on a theme as well.