I cannot identify by the photo which engine is installed, but will say that the mechanic named just about all the oil control seals that are used when the engine is assembled. I.e., didn't leave anything out, and if you replace them ALL, odds are you will fix the leaking seal along with all the others that may NOT be leaking.
The photo looks like the bottom of the oil pan along the side facing the radiator. It appears you have a drop or so on the bottom of the engine, but nothing on the oil pan itself. IOW, a drop here and there, but not a buildup in one position. Of course there may be other spots that have droplets forming. The left side appears to have oil also.
If you have a leak at the end of the engine where the transmission is attached, at the bottom of the 'bell housing', that could be a rear main seal leak. If it uses transmission fluid, it could be the front transmission seal(converter hub). Need more pictures....
A significant amount of oil is not shown in the picture posted. What is your definition of 'significant amount of oil'?
If you have a puddle in the spot where you park, and it is a new puddle every day, that is significant, especially if you need to add oil between changes as the level indicated on the dipstick is in the ADD area. If you have to add a quart every 500 miles, then you have a leak that may be worthy of spending $$ to fix. If you add a quart every 1000 miles, another story, different in that the leak is less severe. You can also consume oil by burning along with the fuel.
I have a V6 with about 155,000 miles on the odometer. I just replaced the cam cover seals, taking roughly 5-6 hours, taking my time, taking breaks, and without use of assists available to professionals. I had a slow seep that would leave oil on the bolts holding the A/C compressor. I assumed(!) that it was seepage down the front (radiator) side of the engine. I replaced both front and rear seals, AND the PCV valve. If you have a PCV valve that is clogged, it may limit airflow through the inside of the engine, where all the parts move and the OIL lives. If it develops pressure inside, it can push oil out the easiest spot it can find. It can develop pressure if the PCV valve is not allowing flow, as some gases leak past the piston rings into the crankcase when the engine is running. ALL engines have that leakage, called 'blowby', to some degree, generally more as an engine ages. So, if the PCV is not functioning, replacing it may reduce oil leakage. You can test for PCV function by having the engine running at idle, and removing the small air tube that connects from the air cleaner to the top of the cam cover. A working PCV will develop a slight suction on that tube if you were to cover it with a digit, say, a thumb. If you get no suction, the PCV may be dorked, sticky, clogged, non-functional by any means. The 4-cylinder engines made by Ford in the past may or may not have an actual PCV valve. Escort engines made in the 1980's used a fix orifice and did not have a PCV, so you mileage may vary.