Speak to Wozza on the forums. He's put a 1.8ltr BP Twim Cam engine out of a 1990 Ford Laser TX3 into a MK1 but used twin webbers instead of the fuel injection. Might also be an option.
Now there is also one other thing that you need to think about and that is the distributor. In the Laser it is at the back of the head, so when fitted into the Escort it will right where the firewall is. Wozza made a 90 deg elbow drive set-up for his, but others have used the MX5 engine which places it on the side of the head, but also has the thermostat housing at the front of the engine as well.
With the thermostat housing, I have seen someone plug the old one at the back of the head and drill a new one into the front of the head and make up an adapter for it to come out from underneath the cam pulleys.
Gearbox wise, use an MX5 box, but you might have to modify it a bit to get the shifter in the right spot to suit you.
This conversion has been done by quite a few people now and is gaining in popularity as they are a good motor and easy to repair and get parts for.
The guys who currently have are are fitting these engines into Escorts are Wozza, Simon (http://www.classic-ford.org/forum/topic.asp?TOPIC_ID=291&whichpage=6) and Mish. Simon is one of the Mods and is currently doing this set-up into his MK1 2 door so he will be a wealth of information, as too will be Mish who just installed a BPT into his MK2 4 door. I think I'm o.k. in saying that you can contact any of these guys with questions regarding your conversion and they will be able to help with the answers.
Good luck with it. Will be a great little sleeper once it's done.
Chippa