Oups... Did nor know LR4 has no drain plug... Agreed then!You are talking about a different style of engine. On an engine with no drain plug and a top mounted cartridge style oil filter (i.e. LR4 engine) I feel that it is best to loosen the filter first. This allows the oil in the filter to drain into the oil pan. Then you can syphon the oil out, once the oil is out you can replace the filter. The filter will have had time to drain and it won't be dripping with oil when you pull it out of the housing.
Even if you have a drain plug I feel that it is still better to loosen the filter first.
If you drain/siphon the oil then pull the filter the half a quart or so of old oil that was in the filter gets dumped into your oil pan and mixed up with all the new oil.
If your engine has a drain plug and traditional oil filter mounted on the bottom or side of the engine you can do it any way you want.
Yes, it depends on where it is located, but not critical anyway... Everyone has their own way. Did not get the part about old/new oil mix. What do you mean, changing filter after new oil is in??