Nucleus always have a positive charge. In case of Hydrogen this is +1e, in case of Helium +2e, …, in case of iron +26e,…
This means that any two nucleus will experience a force pushing them apart. If the charges of the nucleus are higher they will experience a higher repelling force.
For fusion to occur both nucleus have to go through the "force-barrier" of the other nucleus. To go through that barrier a high energy which depends on the strength of the repelling force is needed.
So you see that you need higher energies for fusioning higher-order elements.
The energy usually comes from the kinetic energy(how fast they are) of the two nucleus.
As you might know the speed of the particles is what makes up the temperature of a medium. Meaning that plasmas of higher temperatures are able to fusion higher order elements.

Could localized magnetic conditions[…] be sufficient to create isotopes higher than helium.

No. Magnetic fields only change the direction, but not the value of velocity of charged particles. So no additional energy, that is needed for fusion, could be transferred with magnetic fields.

Sunspots are also known to be of a rather cold temperature(about 10⁴ times smaller than in the center of the sun) which means no fusion should occur.

What happens to those elements in the face of solar plasma?

Since they are heavier I think they would mostly sink down towards the center of gravity.

Is it possible that some of these particles will pick up spare electrons sufficient to change their state?

In plasma there are a lot of high-energetic electrons.
Those electrons could in general combine with a nucleus of the dust and induce some kind of β⁺-decay.
I don't know the probability of such a process, but the product will in most processes be unstable and redecay in a β⁻-decay which releases the electron again. → most of the matter isn't influenced by electrons.

I did some research on the internet and most sources I found were saying that the mentioned glass beats come from volcanic activity rather than from the sun.
I trust these sources, because the amount of higher order elements needed for creating enough glass beads and the amount of energy needed to kick them up to the earth-orbit seem really high. Also for every glass molecule a lot of hydrogen and helium would also come along as they need a lot less energy to spread out.

What if our sun[…] flickers […].

That might be possible, but I don't think that change would be significant for earth. Also such a change should happen on a regular basis. Such a regular pattern cannot be find in the last 800.000 years, but it should be if the cycle would repeat every 12000 years.

source
Also the temperature rise should happen after the mass ejection and not before it right? Because only the mass ejection should warm earth and not the period right before it(As you stated there are more sunspot before the ejection → the average temperature would be lower → the temperature should actually get a bit cooler before it).