For melting down ingots I used an old tank that had compressed air in it. I cut the top off then welding handles to it. You can also use an old propane tank (obviously empty the tank prior to cutting it...). Otherwise old frying pans, steel or cast steel pots. Don't use aluminum or cast aluminum. They likely won't melt but they are close to the temp and the last thing you want is molten lead all over the place.
You could use a casting furnace but I would only use clean lead to avoid drips assuming it's a bottom pour.
As for a heat source I bought a fish fryer that uses propane, it's not meant for the weight of a turkey but I've stood on top of it and it held my weight (200+lbs). Or a proper tube framed turkey fryer if you don't want to bother reinforcing it. Others have used Colman stoves, hot plates etc but those would only do small batches.
For the laddie itself you can buy them or use an all steel kitchen laddie. I made one from a stainless steel measuring cup.
For removing the dross and wheel weight clips I use a large kitchen spoon with holes in it.