Luggage and bags:
Always carry empty bags, you may buy a lot, clothes, silver, mementos, etc.
Clothing/Shoes/Weather Gear: From December to March take warm clothes, it could be colder than you thing, Mexico is not a desert, some times in the city there are temperatures under 32 F
From April to June is very hot, some times it gets 104 F
From June to September it rains.
From September to November is windy and fresh.
Toiletries and Medical Supplies: No need there are a lot of drugstores and hospitals with the best equipment
Toiletries and Medical Supplies: Even Wal-Mart follows local norms and carries 17,000 brands of pads/shields. If you use other products, bring them. How embarrassing would it be to have to ask for these Other Products to be sent in your next care package? Give me a week and I will be able to tell you how embarrassing.