if i'm coming from hkia, what ferry should i board in going to Venetian, Macau? need to get visa?

After you land in HKIA, you can take a ferry from the Skypier to Macau, and you will arrive at Maritime Ferry Terminal. There you can take the free shuttle bus to the hotel.

Without visa, you can stay in HK for 14 days and 30 days in Macao, and you need to provide to reservation of the hotels and the round-trip air ticket when passing the immigration.

If you will stay longer, you’d better apply for a visa in advance.

How many hours is the travel time from the skypier ferry to macao? Do you have any idea how much is the fare?

It takes 50min from Skypier to Macao. It costs 246HKD and 385HKD, respectively for the economy class cabin and the super class cabin.