No question seems to be off limits or silly on here. Many of us have already asked those questions years ago or found the answers to our questions in someone else's post. Please ask whatever questions you may have. A lot of what you choose to wear depends on where you live and the time of year. My surgery was April and I live in northern NY state so it is still pretty cool here (40's). I bought a couple pair of inexpensive sweatpants at Walmart in a size larger than I normally wear. They were nice and warm and comfortable. I think your shorts will work just fine as long as they aren't too snug. The t-shirt dresses you got sound good, too.
I also purchased a dressing stick on Amazon. It came in very handy when I went to take the sweatpants off. I could push them off my feet myself without asking for help in those early days before I could bend over that far. That was the only gadget I got and it was very useful in those early days. I made myself a "bag" for my walker so I could carry around a drink, meds, snack, phone, book, etc. That, too, came in handy. Sending good wishes your way....