"1) Should this be a 300F cook or lower?
2) Approximately how long for 2 pounds of meat worth meatloaf - 2 hours @ 300F?
3) cast iron, meatloaf pan or directly on the grill"
Meatloaf & fatties, I go @ 275, usually do smaller loafs.....would guess 1-1/2 hrs........check for internal temp is a GOOD thing on ground meats.....you want to be right at 165, most likely.....
If you pan, you'll need a second one with holes in the bottom....somewhere for the grease to drip to......these are manufactured or can be made.......
Another way is to cook 45 min. then overturn the pan carefully & cook the rest upside down ....or right side up, youir choice.....depending on how it looks at that pointr.......
I do smaller "personal meatloafs" & they cook just fine & get done slightly quicker........coals banked, or baskets both sides loaf(s) down the middle.......