1) Does the seated car have air-conditoner? Are the seats able to be reclined? And are the place to bath or shower? Will there be a place for my luggages?
Yes, it should be air-conditioned. No, shower is available only in certain sleeper carriages. Depends how big is your suitscase, for a normal size luggage there is enough place. Compartment will look something like
this, you can see baggage shelf above the seats
2) For the couchette car for 4 seaters,is it air-conditioned? Are there place to bath or shower? Will there be a place for my luggages?
Yes, it is also air-conditioned. No shower. What concerns luggage, well if it's 4 people than you can use upper berth for your luggage, but in case it's 6 people in one compartment, then it can be a problem and you will be forced to keep your suitcase next to the window or even between the lower berths.