If you want to highlight the staircase wall then your could use earthy colours such as a yellow ochre! The wall could be enhanced even more by using suitable frames and making a good collage composition for all the photos that you have (I can see many lying on the dining table). This colour would match well with wooden furnitures

any exposure to water n sunlight will decrease the life of the wood.. no matter what wood you use. in most of the cases, paint protects the wood when it's exposed to air directly... but if u use polish.... then you are actually gonna waste your money.... hope that is what you were looking for. cheers !!

Paint ceiling with white color Have perpherial false ceiling , install strip LED lights , this way you can have indirect day light .

When dimensioning a classroom or teaching space, the best rule of thumb to produce both good sightlines and efficient layout is as follows: the space needs to be slightly rectangular, but NOT long and narrow. If X = 1, then Y should = 1.2 ideally, and no more than 1.5. Consider a comfortable space of 12 sqft. per student so if you have 6 students in a classroom then 72 sqft. + teaching space and walking space (60 sqft. or more) so say roughly you need 130 - 140 sqft. of space per class.