What is a normal car battery drain for Ford Escort LX 1998 when everything is off?

Anything over 30 milliamps is excessive

What you're seeing for a drop in voltage is insignificant. A fully charged battery will read close to 12.6 volts. A good but discharged battery will read close to 12.0 volts. You're right in the middle which suggests it's not fully charged yet. You also have a "surface charge" that you are reading at first. As the electrons get absorbed into the lead in the plates, the voltage will go down a little. Removing that surface charge to get a more accurate reading on the battery's condition is why the mechanic will put a high load on it for a few seconds, wait a bit for it to recover, THEN perform the actual load test.

Since you appear to understand electrical theory, it might make sense that a battery charger will not exhibit the same characteristics as when the battery is charging in the car. Chargers put out a rectified single-phase sine wave but generators put out a more steady rectified three phase output. For a large percentage of the time, a charger's output voltage is less than 12 volts, and it even hits 0 volts momentarily so it takes a lot longer to charge the battery that way.

Getting back to the problem, a 200 milliamp draw is way too much. Chrysler says 35 ma is the maximum allowable and at that rate they guarantee a good battery will still start the engine after sitting three weeks. Other manufacturers use similar specifications. Some go as high as 50 ma, but 200 is too much. Regardless, that will not kill a battery overnight. I don't know what a "BTN" fuse is for but if it's related to a computer on the car, some of them have to time-out before they go to "sleep" mode. Until they do that, they could draw as much as three amps for up to 20 minutes. There's a special procedure for measuring current draw on those cars because the measurements have to be taken after all computers have turned off, and disconnecting a battery cable to insert an amp meter will wake those computers up again when the cable is connected.

What I'd recommend first is to measure the current draw after 30 minutes to see if it drops lower. If it does, consider that normal. Next, test the charging system by measuring battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is low, the battery will not fully charge. If you find it's a little high, have a load test performed on the generator with a tester that measures ripple. Most professional testers do that. If there is one bad diode in the generator you will lose exactly two thirds of the rated capacity. That means a 90 amp generator will only be able to produce about 30 amps. That's just enough to run the fuel pump, ignition system and injectors, a few lights and the radio with nothing left over to charge the battery. With all other electrical loads turned off, the clue to a bad diode is the battery voltage will be a little high because the voltage regulator is responding to the drop in output due to the one missing phase of the three. Output voltage drops real low one third of the time and the regulator responds by boosting output. It takes too long to go back down during the two good phases so they put out more voltage than desired. Even though the average voltage is too high, the system can't maintain it when you turn on more loads such as the heater fan, head lights, and wipers. A bad diode will show up as very high ripple voltage.

If the voltage is too low, look at the voltage regulator on the back of the generator. It's held on with four screws in a rectangular pattern. In addition, there are two identical-looking screws corresponding to the two brushes. One might have a gray plastic cap covering it if it hasn't fallen off yet. The other one has an arrow pointing to it with the words "Ground here to test". As you stand behind the generator looking at the rear, with the two screws at the bottom of the regulator, that one that you want is the left of the two. If you use a piece of wire to ground that screw while the engine is running, it will "full-field" the system by bypassing the voltage regulator. Only do this test long enough to get usable results and do not raise engine speed as there will be nothing to limit output voltage. That voltage can easily go high enough to destroy computers and burn out light bulbs. Also, only do this test if system voltage is low. When there is no change in battery voltage between engine stopped and running, this test identifies whether the generator or the voltage regulator is the cause. If the voltage is around 12.6 volts with the engine running, and grounding that terminal has no affect, suspect a worn brush. New ones come as part of a new voltage regulator. They can be unbolted but I never checked to see if they can be purchased separately.

The more common problem is the battery voltage is around 12.6 volts and grounding the test terminal makes it go well over 16 volts. That is proof the regulator is defective and the rest of the generator is working. It can be replaced separately by removing those four screws. On most front-wheel-drive cars that can even be done without removing the generator from the engine.

Here's some drawings I made to explain ripple and how it differs between a battery charger and the generator on the car. If it doesn't make sense, don't get all wrapped around the axle in trying to figure it out. I suspect the tiny drop in battery voltage you're seeing is irrelevant to your problem. Rather than testing the voltage after putting the battery on a charger, let it charge in the car while driving a good 10 - 20 miles, then stop the engine and disconnect the battery. Measure the voltage a few minutes later and again in a day or two. My guess is it will be higher than 12.1 volts. Recheck the charging system voltage too at some point.

Doesn't matter where you put the switch. You're working in a series circuit so a switch or anything else that causes a break will have the same effect anywhere.

Here's the "story" I gave my students because electrical theory is very hard to understand for people who work best on things they can see and touch: Imagine water flowing down a river. It flows to the ocean, evaporates, a cloud floats back up over the land, gets torn on a church steeple, rain falls out and trickles into the river and starts all over again. That is like a giant series circuit. It doesn't matter WHAT you do; anything that stops that sequence of events stops the flow of water. You could put a dam on the river, or you could put a huge sheet of Saran Wrap over the ocean so the water couldn't evaporate. The cycle can be stopped anywhere.

In your car, current flows from the battery positive cable*, through the fuse, through a switch, a light bulb, to the body sheet metal, through the negative battery cable, and back into the battery. That is a complete series circuit. A break anywhere in that circuit will cause the current to stop flowing just like the water stopped flowing in my story.

*Now, before anyone tells me I messed up, current actually leaves the battery's negative post and comes back on the positive post, but it is customary to draw electrical diagrams starting from the positive post. That is a technicality that has no significance and makes troubleshooting those circuits easier to understand.

Pardon the interruption but Mike the battery is toast. It has plate damage and is internaly draining

I suspect the battery is going to test fine after charging it. You would have to leave the battery with the mechanic, or the whole car, so they can retest it after a day or two of being disconnected and not charging.