Is the fuse's in the same spot 2000 and a 2001

Usually the fuse has a bare spot over each fuse leg, use a test light on each bare spot, if the light comes on, the fuse is good. To use a test light the fuse circuit has to be hot. Also, I suppose you can do a continuity test on the fuse, no voltage. You could try looking at the fuse, sometimes if it is blown, it is very noticeable, sometimes not.

I haven't looked at your fuses. Most fuses have a bare spot on top, over each fuse leg. You can use a testlight on the two bare spots on top of the fuse. If the testlight lights up on both bare spots, then the fuse is good, plus, the fuse circuit has voltage.

If your talking about the headlamps, that fuse circuit may not go hot without turning on the headlamp switch and or ignition key. I haven't looked at your wiring, yet.
Usually it isn't the fuse, I hardly ever get that lucky.

2000,2001 & 2002

In a pinch, yes you can use a 20amp in place of a 10amp as long as you have repaired what blew the 10amp.
It needs to be changed to the correct 10amp ASAP.
What happens is the next time, the 20 becomes a 30, becomes a 40 becomes a ... and the wiring harness burns up.

The 2000,2001 & I believe 2002 Lincoln LS
have a 5R55N Trans

The 2003 thru 2006 have a 5R55S Trans

Replace -- you mean rebuild yours or get a rebuilt
from Jasper,etc

NEVER install a used trans in ANYTHING

There are two fuses that are next to it, one is a head light and the other is a fog light, those would hot all the time. There is a fuseablle link or a bigger fuse feeding this box. You can look for a whole wiring diagram on autozones site if you make a free account and look for the repair guides, then electrical. If not you need to get a Haynes manual or go to all data using the link from autozone. These wont be free.

yes not sure which one thou

Look at the color and Number on it If both fuses have the same amp rating you can swap them to test. If they are different amps you could just blow the fuse again if its a lower amp rating, or damage your Climate Control system if the fuse has a higher amp rating than the original. By the way, all the GM vehicles I've owned had several spare fuses in side the fuse panel.

may need to change your head gasket?

As long as everything is working, don't worry about it. There will be blank fuse spots in your fuse panel. Those are for other options you may not have have, so there isn't any wiring to those spots.