Yes, this game is basically AWL with a face-lift. A lot of the features in AWLFG are in here. I'll just list the ones that I know about so far that are not in either AWL or AWLFG.
Ability to Marry Lumina
Yes, you can marry Lumina in this game! Since she's younger than the other girls, you can't marry her at the end of Chapter 1. However, you can get engaged to her by the end of the first chapter. Whether you marry her or not, she will be an adult at the start of Chapter 2.
I'll try to list all of Lumina's events later… Sadly, I can't take screenshots of Oh!WL (WinTV won't work with it). Maybe I'll have to give my digital camera a try. Anyway, it's a bit hard to document all the events without screenshots to look at. I'll just say these two things right now: Lumina's diary is located on the table against the back wall of her room, and most of Lumina's events trigger when you either enter or exit the mansion.
Ability to Have a Son or Daughter
Yup, you can have a daughter. The daughters all look exactly the same in Chapter 2, which is a bit freaky. I have as yet to get past Chapter 2 in a file (That's what happens when you try to play multiple files at once).
It was once thought that having a boy or girl was random, chosen for you at the beginning of the game. That may be true to an extent, but there is a way you can make sure that you have a daughter! Just go and visit the Harvest Sprites. See that pot against the wall? It's a magical pot! Keep talking to the pot, until it finally admits to defeat (apparently, it hates being talked to) and tells you to go talk to one of the Harvest Sprites. Do so, and the sprite will ask you if you want a son or daughter. Select whichever you prefer.
It sounds crazy, I know, but that is a 100% guaranteed way to get a daughter!
You automatically change clothes according to season. Once you get married, your wife changes her clothing.
From left to right, it's the clothing for Spring, Summer, Fall, and Winter.
Different Colored Animals
Well, I still haven't been able to verify if there are different colored chickens yet. But horses? Yes. I've gotten a dark brown (almost black) horse a few times, and a white horse once. There's no difference in the speed or personality of the horses.
Self-explanatory. You can continue to play the game even after the ending.