If you've got the cash, any engine swap is possible. That said, 347 is one of the better ones. K Member would have to be changed, as the 4.6 has a different motor mount. A V6 unit or aftermarket meant for a SBF would be needed. Transmission also doesn't bolt up. The rest depends on your induction setup.
Wiring depends on your induction. It's different if you're going carb, standalone EFI, trying to reuse the 4.6's EFI, etc. It should be possible to use the 4.6's EFI system (setup as a waste spark like the 5.0 Explorers had), but I don't know if anyone has done it.
As for emissions, if you're going EFI, you can probably tune it to pass emissions, assuming a 347 will pass emissions (I've never looked at that aspect).
Swapping in a completely different motor than what the car originally came from the factory with will not pass the visual part of any ODB2 inspection. This problem is in addition to getting the PCM to manage a completely different motor than what it was designed for.
If you live in an area where it's necessary to pass an ODB2 style inspection this is not the swap for you. Your car is too new.
This is a common swap I've tuned countless of them with no issues. As long as your county isn't too technical about the engine swap it will pass emissions perfectly fine. If all they do is a quick look over for emissions components present and do a plug-in obd-2 test then it will pass perfectly fine. I have yet to have one fail emissions.
As has been stated you will need a v6 k-member since it has the sbf motor mount setup making it practically bolt in. Your modular bell housing trans will not mate up to the sbf. You will need a 4r70w auto trans from the same v6 mustang you snatched the k-member from. The trans is stout so no worries about rebuilding it or anything I've pushed 600rwhp through bone stockers and never had any problems. Your cheapest option would be to get a marauder specific torque converter and you will need a new flexplate as well. Here is a reference thread with links http://forum.efidynotuning.com/viewtopic.php?f=24&t=2562&p=32896#p32896
Verify your imbalance as a 347 could be balanced either way 50oz, 28oz or even neutral.
You will need the balancer (again check imbalance), 35 tooth reluctor, timing cover, crank trigger, cam stalk and cam sensor from a 99-01 explorer 5L. Cut the cam sensor connector off the donor vehicle as well to mate to your existing wiring.
Toss that on your 347, slap it in the car with the new flex and trans. Everything should plug right in. Take the original coil on plugs and rip the boot off the coil. Get yourself a set of ls1 plug wires and they can be snapped on the coil. You can fab up a bracket to secure the coils to the valve covers if your up to it. No reason to go coil packs.
The remaining air inlet ducting, coolant hoses, driveshaft, etc.. is all trivial.