The flood date does work in synchronization with Chunakah, but not as you think because they came out of the ark one month before
Chanukah occurs in the "third month, 25th day", but they came out of the Ark on the "second month, the 27th day).
, on the 360 calendar of the prophets
there is often a 30-day variance. This means that a certain day may be the second month and also the third month, depending on which calendar. I discuss this on my website. (Thus, the 1290 days of Daniel 12 and the 1260 days of Revelation 12, can come together at times and land on the same day, being 30 days difference.)
If we allow for the possibility of the 30-day overlap of the two 360-day calendars, there is a potential pattern that still emerges that one day God may use in the future.
The narrative of the flood date follows this pattern as listed according to when each time frame is mentioned. (The narrative repeats some time frames twice)
7 days of waiting for the Flood (7:4)
7 days of waiting for Flood (7 :10)
40 days of Flood (7:17a)
150 days of water triumphing 7:24)
150 days of water waning (8:3)
40 days of waiting (8:6)
7 days of waiting (8:10)
7 days of waiting (8:12)"
Besides the obvious pattern, you will notice that the use of round numbers means that the seven days at either end is being forwarded by even numbers of 40 and 150. This is true of Kislev 27th when they came out of the ark, it being 40 days and exactly half-a-year from when the ark rested on Mount Ararat on the "7th month, 17th day", which was 150 days from when the flood began.
The point is that the flood story begins with the seven days in the ark waiting for the rains to begin, and this seven days is forwarded throughout the narrative so that each major event in the account has, or can have assigned, a seven day period that precedes it. (This effect occurs in the dated narratives in the book of Ezekiel as well.)
Thus, the 27th when they came out of the Ark also has a shadow seven days before it when aligned with the rest of the dates. That is, from the 20th to the 27th of Kislev.
Because Chunakah begins at the end of the 24th day and start of the 25th, and since a day in the bible runs from evening to evening (not midnight to midnight), thus Chunakah, "the seven days of lights", begins exactly in the middle of the final seven days that they waited until they came off the ark. This assumes that they came off the ark early in the morning of the 27th day, which is the only logical time for such a major endeavor with so many animals. The seven days to leave the ark intersects the seven days of light.
(The seven days of lights also has a special 8th day. I won't get into that now.)
This pattern is made more clear when we realize that they were using the 360-day calendar, literally or symbolically.
This is why there are 150 days until the ark rests on Mount Ararat, not 152 if it was a 365-day year, and not 148 if it was a regular Jewish calendar year.
Chunukah commemorates the cleansing of the temple in 168 BC, which was prophesied in Daniel 8.
As I constantly show in my websites, when you count back the predicted 1150 days from the seven-days of Chanuka (the time that the temple was besieged and then defiled), this seven begins at the seven-days of tabernacles three years earlier. (70 + 360 + 360 + 360 days = 1150.) Chanukah and "the seven days of light" begins 70 days after the seven days of Tabernacles, and therefore, so again, Tabernacles is also 1150 days before Chanukah.
The point of this is that the Kislev 20th to the 27th of the flood is also seventy days before the Day of Atonement and Tabernacles. This underscores the pattern being used here in the bible, a pattern based upon seven or seventy, and which corresponds to all the feasts of the bible, including Rosh Hoshanah and the Day of Atonement. (Even as the literal "second month, the 27th [and 20th] day", is still, importantly, 40 days after after the Day of Atonement and Tabernacles.)
And all that
was simply to say that, "yes, it is not a coincidence that the anniversary of when they came out of the ark falls within the days of Chanukah!"
One last note, as you mentioned, no one knows for sure if all the flood dates should be moved up six months in keeping with the religious calendar given to Moses based upon a spring New Year. I am confident that the ambiguity is on purpose and the dates should be studied as such. This would forward the "second month, the 27th day" when they came out of the ark to when Jesus ascended up from this earth in a cloud, and thus the seven days from the 20th to the 27th is 40 days from the Triumphal entry into Jerusalem unto His resurrection (according to the synoptic Gospels of the first three books of the bible).
Oh yeh, this extra 30 days of overlap, by the way, means that they would have been on the ark 370 days, but with the extra 30 days it symbolically makes an even 400 days, and is in agreement with the "40 days" that frequent the narrative of the flood.
Kind of complicated, i know. But after you have studied it a while it's not too hard to grasp.