I agree, check-in at All-Stars can be very lengthy. Even if there is no line, the check-in agents have to do their entire spiel of getting your ID, getting your payment, if required. If prepaid getting your package components to you. Printing room keys, adding charging priveledges, etc., etc., etc.
The only time I have had a short check-in was about 1am, I was solo, no tickets, and I told them upfront I had been there a gazillion times. I had my ID and credit card in hand and told them upfront that I wanted express check-out and charging priviledges and no passes. That was super speedy by WDW standards and took just under 10 minutes.
Unless you absolutely need your room key/park passes by checking in, I would just leave your luggage with bell services or in your trunk, and head straight to your midday activity.
That's what we usually do, then check in late at night.
Carol