Step 1. Register as a small batch manufacturer. There is no cost. If you don't, you will have to test for some things, Dyed leather would need testing at your expense. If you are registered, you can use statements from the leather suppliers of their testing.
2.. you are going to need CPSIA labels and FTC labels. Since you are using wool, wool labeling is also mandatory even if you do not normally need FTC labels.
3.. Do not use ties at the waistline, use encased elastic. Children under 16 can't have drawstrings or ties at necklines and waists except under strict length and attachment guideline. Drawstrings are generally the biggest issue for clothing recalls. Just don't, find another method. Ties can get caught in stroller wheels, car doors, highchairs, cribs, ride on toys, etc.
4. Get used to the legal jargon. It will be a part of your business life. If you have a specific wording you don't understand. Copy paste it and I will try to explain it as it applies to your items. It would help me if you could convo me pictures of examples of what you are going to make.
4.