Can freeze plug be replaced with engine in car?

Hello everyone,
I have a 1998 Jeep Grand Cherokee with the in line 4.0 engine. Some of the freeze plugs show leakage.
Does any one know if these can be replaced with the engine in the car?
It looks like I would have to remove the intake and exhaust manifolds but I do not know if I would have enough clearance to replace them.
There is 5 plugs, from the front of the engine no. 1 looks ok, it is no.3 that is really bad and it seats right in front of the exhaust manifold.

I haven't done the job, but after looking at mine, IMO you should be able to do it with the engine in but it will be a little tight.