Hm. Maybe you're right. I thought that alternating whip and holy water required at least a II.
Confirmed that alternating whip and holy water requires a II icon! The holy water takes a second to burn on the ground - longer than a single whip strike.
I developed a good strategy to beat Dracula somewhat reliably.
1. Collect about 40 hearts from the candles in the room before Dracula's room to give you enough to work with
2. Leave the 4 candles in Dracula's room untouched as you walk into the room
3. Walk all the way to the left and whip the leftmost candle to collect the holy water. While you do this, Dracula will start to spawn.
4. Destroy the 2nd and 3rd candles with the holy water. This increases your chances of getting a II. Or, I suppose more accurately, works on incrementing the hidden ticker towards earning the II.
5. As opportunity allows it in Dracula's first form, when Dracula phases in and solidifies, through a holy water into his body. When he opens his cape to fire fireballs, jump over them and whip him in the head. The holy water can destroy his fireballs, and there's a probability they will give hearts, and therefore also II icons. The holy water here is not to do damage to Drac, but to give yourself a chance to get a II icon. Eventually you will get a II from this, although it makes the first form a bit more challenging.
6. It is definitely possible to get two whips in per phase. The first has to land as soon as he solidifies, so the position of the phasing has to be ideal.
7. With a II, the second form is trivial. Alternate holy water and whip, and he will never get a chance to jump or shoot fireballs.
8. You played the greatest role in this journey.