There are plenty of tables that extend without a drop leaf. In one style (usually more modern) the extension slips under the rest of the table with a spring mechanism, making the table surface look like it has a double thickness when you aren't using it. In the other style (usually more traditional) there are leaves that can be put into the table. The latter takes more work to assemble each time you want to extend.

planning of building first floor of my 10 year old home , confused about construction of bathroom attached bedrooms considering size and ground floor plan constraints

why are you extending that living area taking up the balcony ?......i mean it looks quite well having a balcony as you can see the view of the outside and serves cross ventilation as well rather u can decorate your living but if u really want to extend that area u can add up false ceiling but with that i think u might end up having less height of the room allover or particularly from that portion of the extended area ...which might look abrupt to eyes . there is another way of using that beam ....you can use that area for putting ac so that it won't look odd. something like this and can use your area hanging that jhula like so in the picture and for once u should think once, extending that area i mean u can use low height sofas for minimizing the space and and your room will appear larger .somewhat like this ........i hope u understand my point .

The local contractor working in your area will know all about the extensions permissible by DDA. You just need to match the exteriors with the existing elevation of the building.