Can I use free public bus H1 to leave my hotel (the wharney guang dong) to HKIA?

No, the bus H1 doesn’t lead to the airport. You can take the free shuttle bus H1 to HK Station, where you can take the airport express train to the airport.

From the ferry terminal, there is no direct bus going to the hotel. But you can take the bus No. 3C from the ferry terminal to Nelson Street Mong Kok. Then you can reach the hotel after 5 mins walking. The bus fare is HKD5.8 and the travel time is about 20mins.