Howdy y'all. I'm new to the Delta family (despite being a SkyMiles member: I used it just to link it with Lyft back then) after years of exclusively flying WN, AA, and HA, so bear with me:

I booked DL Main Basic on the earliest flight from DFW to SEA. It says the flight will be on an A220. Now, I understand that with main basic I cannot select a seat unless I pay extra to upgrade to Main Cabin. Here are a few questions.

1. Has anybody flown DL DFW-SEA early in the morning? Was the flight full?
2. Any chance of me getting a window when I hit "check-in" at T-24 hours or T-3 at the airport? I know since this is an A220 with a 2-3 seating, I'm sure my chance of getting a middle should be less, at least compared to a 320, 321, or 737. Do they let you pick whatever is available, or do they auto-assign you?
3. How's DFW TSA at 4am? I plan to check-in for my DL flight at around that time frame - and P.S., yes, I do have PreCheck.

The reason I ask question no. 2 is just to familiarize myself just in case the system differs from AA, HA, AS, and WN. I can't say for AA since I usually pay considering their flights out of DFW is very crowded and WN for obvious reasons, but for HA and AS, I've always check in at the airport at T-3 and managed to get windows on their lowest subclass. I understand the risks, so no need for the "if you really want the window seat, pay. Don't ask people to move" comment - despite me loving to take pics outside the window, I'm never a guy who asks people to move just for it. Help me take pictures outside the window only during takeoff and landing, yes, but move, absolutely not.