Well, for starters it does not sound like you have the same engine in the first place so I don't know that I can answer that - you said you pulled the coil, that sounds like a Duratec not a Zetec - you haven't posted the make/model/plug number or the exact engine. If this is Duratec have you read the The Duratec Sparkplug Sticky in the Duratec performance section? Are you using the right plugs?
Pulling the head on any dual overhead cam engine is certainly more complex than a pushrod engine. If you are careful and your timing belt (or chain if the engine is so equipped) hasn't broken you won't have to reset timing - but you should be prepared to have to setup timing again.
On the Zetec the head is supposed to be "skin milled" anytime a new head gasket is used or it won't seal. You have to use new TTY bolts. You really need to use compressed air to clean the head bolt holes out properly. You need to replace a lot of gaskets. There are different engine variants and you have to get the correct gasket set for yours and the gasket manufacturers aren't that helpful in identification in advance so you have to be buying new parts when you have the head off and the engine parts strewn all over the garage, you can't get everything in advance and just do it. You need a factory service manual. And the list of details goes on and on. I took about 80 pictures during the operation and referred to many of them putting things back together. I can't speak for the Duratec but I suspect it's the same deal.
It was a far cry from the last head I pulled - off my 302 V8. That one was a piece of cake compared to the Zetec.