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The moire' patterns occur where the focus is a little too sharp and the scan line structure beats with the CRT screen structure. You can show this easily by adjusting the focus in and out or even by adjusting the vertical linearity or height slightly to change the line spacing. Nothing can be done to fix this.
Regarding the jail bars: I lost track of what set this is and how it's constructed. If it has more than one printed circuit board, make sure all the boards are well grounded to the chassis at their ground points. The ringing frequency will be well within the capability of almost any scope - it looks to be 10 or 12 times horizontal, so that's 200 kHz at most. The problem is, if it's getting into the video and caused by ground currents, the scope would need to be hooked to the same ground point and hot point as the video circuit to see whatever the video circuit is seeing. So, you have a huge number of possibilities of how to hook up your scope. Also, it may be difficult to see if it's getting in at a low-level point in the video circuit and your scope does not have much gain.
As others have said, it might not be in the video, but on one of the CRT electrodes. Does the strength increase and decrease as you turn the contrast (picture) control? If so, it's in the video. If not, it may be getting to the CRT through some other path, or getting into the video after the contrast control.
If there are multiple printed circuit boards (or just multiple ground points on one board), it may be worthwhile to connect some of them to each other or to the chassis with ground wires and observe what happens to the jail bars when you do so. You may find some hot spots this way.
Good luck!
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