I'm sorry this is an image from Houzz but to give you an idea. However, you can plot on a graph paper the walls and doors of your bathroom. Then cut out other bits of paper to scale to represent the dimensions of the tub, toilet and vanity you have in mind. Now move them around to fit. It is really the best way to work out the ideal layout for your bathroom. Hope this helps

Based on the dimensions you have given and the religious aspects you mention you are very restricted in what the layout can be. The best solution I see means you have to move the door towards the south by 36". I suggest you make it a pocket door retracting towards the south wall. This leaves 36" x 60" of space on the north wall for either a shower or tub. The vanity would be on the west wall ( across from the door) spaced away from the tub or shower around 12". Make sure the vanity cabinet is shallow, no more than 21" deep. The vanity should be able to be about 48" wide. The toilet will go on the South wall with the right side of it close to the East wall. Code calls for approx. 33" of width for the toilet overall. If budget allows you could continue the vanity cabinets into the corner of the south wall however keep in mind that most of that area that will be next to the toilet and not easily accessible. But it would provide extra storage or counter space. The sink will have to be centered in the 48" part of the vanity. You could also frame out the southwest corner to capture the side of the vanity instead of a longer vanity. Hope this helps.

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.

Thanks for both of your responses CUBSpaces team and Shweta from Shades studio. It really gives a clarity about possible consequences. I am now doubt free about changing whole things in Bathroom as it will be interconnected. However will appreciate your opinion on few things: 1. Kitchen wall tiles: I have those from countertop height to roof(almost area of 6X15 feet) which are good and not hollow. I changed countertop 5 years back without any damage to these tiles. It might cost me another 10-15 K, but I feel the whole process and quantity of wasting old good tiles makes me little sad. 2. kitchen countertop: Made new around 5 years back. I don't expect to get it all intact. But large pieces can be cut and can be used as top for other freestanding structures like dishwasher, front load washer, heighten base cabinets, etc. 3. Plywood: I don't mind giving enough labour charges for old sheets recycle. I am planning to use doors, loose sheets(like kept on bed frame of settee frame.) or parts of big frames like settee. I am keen on reducing waste than to save money. You can see various DIY ideas by western people, who remove or sand laminates and re-paint furniture, or carefully remove hollow tiles and re-attach them. Some are also re-painting ceramic tiles. I am just asking myself: Are we creating more and more waste by use and throw approach every 10-15 years, just because we can afford it?