Help with new gauge setup

Hi guys,

I'm planning to install an aftermarket water temp gauge on my car. The engine is a 360, stock cast iron manifold. While I'm at it I was thinking I'd add an oil pressure gauge, if it's not much more of a hassle.

Was thinking of going with mechanical gauges for simplicity.

Are any of the pictured locations (red arrows pointing to each one) suitable for mounting of the water temp or oil pressure gauges?

1. This is a tapped hole on the passenger's side with nothing in it.
View attachment IMG_2623.jpg

2. Just to the driver's side of the thermostat housing. There's something in there, looks more substantial than just a plug - is it an old gauge sender maybe?
View attachment IMG_2620.jpg

3. This one looks like it's tapped to vacuum, since it has a plastic fitting screwed in with two rubber hoses. The hoses are plugged so it's doing nothing at the moment.
View attachment IMG_2622.jpg

There's also something on the far back of the engine that looks like it could be the oil pressure warning light sender. Too far back to get a good picture, it's below and behind the distributor. Right now the sender (if that's what it is) is not hooked up to anything, is that what I'd want to swap that out with the business end of the oil pressure gauge?