Resistance seems Ok, but in the pictures it looks like you have dirty points, and I’m willing to bet the condensors need to be replaced. Points can be cleaned and don’t need to be replaced. But when you clean them clean all around them not just the contact surface.

There are wires going to the kill button on the mag plate that can make contact with ground "if" the insulation goes bad, but that is rare. On coils that fire 2 plugs at the same time, the test for continuity is between the two secondarys. You won’t get continuity from one secondary lead to ground..so your test was correct.

Your caps are bad I bet. An analog meter will not show leakage or capacity of the cap. Also your replacement caps should be rated at 800 volts & are very important how fast the cap accepts & discharges. Most 400 volt caps have a slower rate & will fail in time. The cap is rated in Dv/Dt1000 or higher & the dissipation factor of 0.05% or LESS!! manufactureswho make caps that perform with high Dv/Dt’s will have that parameter in the description, if not it is not there it is safe to assume the cap is for general use & will not last in a magneto. G o to Newark.com & in the part box type in mkp1839 084hq. These caps are rated for a magneto. Be sure not to forget the suffex hq as it means high quality. I have researched this very much & electronics is my hobby. Vishay is the brand cap. You must mount them in your can but they fit most cans. Anything less & you are asking for failure. 😉 P.S. you need a Merc o tronic or Stevens cap tester for good test data. Check your service manual for placement. I have one & can scan & send the pages needed if needed. jeff.50@cox.net.