You will want to get the power level to something suitable to the desired historical level. Assuming you want something more typical of a Shaw Brothers style wuxia film set in the Song period, I would probably cap out the Qi ranks at 7 or 8, get rid of profound techniques and not have anything like a path to immortality (treat that as myth and legend). If you want more supernatural elements, by all means open up this cap. If you really want to bring things down, cap it at Qi 6.
Also I would be careful in distributing techniques in the setting. Really focus on which manuals contain which techniques and which sects possess them.
You might also eliminate or reduce the number of monsters.
Assuming you want a lot less supernatural, I would generally treat gods, monsters, etc as myths. Also replace the gods in the setting with real gods from Chinese Myth and Legend. For example treat the Enlightened Goddess as the Jade Emperor and treat Hen-Shi as Guanyin (and treat the Hen-Shi cult as Buddhism). Obviously add Buddha.
Religions and philosophies can easily be keyed to real world counterparts:
Dehua=Confucianism or Neo-Confucianism
For sects this is largely up to you. You should be able to port in the existing sects and place them where you want. But you can also add or replace them with the traditional martial sects from wuxia (wudang, Emei, Beggar Sect, etc). Many will easily fit (Nature Loving Monk sect is essentially Beggar Sect), some may take tweaking.
The good thing about doing real world song dynasty is you can find really helpful and detailed maps that include cities and provinces. So this is probably going to have more detail than the maps in the rulebook. The Deiter Kuhn book I mention below has good maps of the provinces as well as maps of the roads in Northern Song. The book Commerce and Society below has a very detailed map of the northen song provinces with key cities (quite a few cities actually).
I don’t know how much you know about Song Dynasty but I would say the following books are useful to get some basic info:
The Age of Confucian Rule: The Song Transformation of China, Deiter Kuhn
Commerce and Society in Sung China, Shiba Yoshinobu (translated by Mark Elvin)
Crossing the Gate: Everyday Lives of Women in Song Dynasty, Man Xu
Religion and Society in Tang and Sung China, Ebrey and Gregory
There are other books I would recommend as well, but this I think covers the basics enough without breaking the bank. If you only want one: go with Age of Confucian Rule. That will give you the history and some key cultural details. Also the bibliography and footnotes of that one can be very useful.
MOVIES AND OTHER RESOURCES
Song Dynasty has a lot of good material around it. I would consider drawing on some of the following for inspiration:
Eight Diagram Pole Fighter
The Four Trilogy
Legend of Condor Heroes (the books, the TV series, movies like Eagle Shooting Heroes)
The Water Margin (Book and Movie)
Demi-Gods and Semi-Devils (book and/or series)
Battle Wizard (based on Demi-Gods and Semidevils)
The Delightful Forest
The Patriot Yue Fei