my observation from that recording is that you are definately off a cylinder and firing on only 3 or even 2That's a good idea with oil pressure gauge. Do ya screw it in to where put oil? I have a bunch of pressure guages.
I sure hope it isn't a rod thing. I'm not a rich man....don't think I can afford new engine. Here is what it sounds like if you can make out the noise
until you have that sorted it is very hard to work out the rest of the noises but it doesn't sound great unfortunately, I don't think it is a bearing though, as bearing knock will get worst as the revs go up
oil pressure is measured from the oil pressure switch which is at the back of the engine to the right - it has a rubber cap on it and is just below the thermostat housing slightly to the right