I assert the following is true:
Either: electrons are made up of (two) quarks Or: Quarks are made up of some kind of smaller particles, which also make up electrons.
I think this must be the case because of the charge matching of electrons to protons, which dictates there must be some kind of kinship (or a coincidence of unfathomable proportions).
Is this true?
Electrons and other leptons are, as far as we know, fundamental. They are not made out of quarks, they are not made out of anything! Neither of your assertions has any empirical evidence going for it.
However, it seems you are really asking for reasons for charge discretization, since you seem to get the idea of your assertions from the charges of electrons and protons being integral multiples of quark charges. That charge comes in integral multiples of some fundamental charge unit does not mean that all things that are charges are made out of the same things carrying only that fundamental charge unit - it's perfectly possible to be fundamental and have more charge than the smallest charge, however, it is not possible to be not an integral multiple of that smallest charge if one of two things is true:
Magnetic monopoles are possible. If this is true, then Dirac's quantization argument directly shows that all charges are integral multiples of a smallest charge, but it does not imply that all charges must be made out of something particular.
The gauge group of the Grand Unified Theory of strong, weak and electromagnetic forces is compact (non-compact gauge group also carry a host of other difficulties with them, so this is a reasonable assumption to make). Again, a completely general property of the theory forces all electric charges to be integral multiples of a smallest one, but says nothing about their composition.
So, although not all charged objects need to be made out of the same stuff, the discreteness of charges is probably not a "coincidence".
You are not the first to try think that one more undelying onion level ( or matriuska) lies within what are considered fundamental particles at present. Back in the late 1970s when the quark model was established , preons were the next hypothesis as the subcomponents of quarks
A number of physicists have attempted to develop a theory of "pre-quarks" (from which the name preon derives) in an effort to justify theoretically the many parts of the Standard Model that are known only through experimental data.
Other names which have been used for these proposed fundamental particles (or particles intermediate between the most fundamental particles and those observed in the Standard Model) include prequarks, subquarks, maons, alphons, quinks, rishons, tweedles, helons, haplons, Y-particles, and primons. Preon is the leading name in the physics community.
For example, the rishon model
has two kinds of fundamental particles called rishons (which means "primary" in Hebrew). They are T ("Third" since it has an electric charge of +⅓ e, or Tohu which means "unformed" in Hebrew Genesis) and V ("Vanishes", since it is electrically neutral, or Vohu which means "void" in Hebrew Genesis). All leptons and all flavours of quarks are three-rishon ordered triplets. These groups of three rishons have spin-½.
.....
In the expanded Harari–Seiberg version the rishons possess color and hypercolor, explaining why the only composites are the observed quarks and leptons. Under certain assumptions, it is possible to show that the model allows exactly for three generations of quarks and leptons.
The group structure observed in the data can be described.
The reason none of these proposed models is accepted as the model of elementary particles is because there is no experimental indication that a substructure exists within electrons and quarks.
Quarks were hypothesized by the observed symmetries in the hadronic resonances , i.e. to fit the symmetries seen in the data, but as late as 1980 the great Feynman supported his parton model, which had no separate existence for quarks, because there was no experimental indication of a substructure to the proton. Once deep inelastic scattering demonstrated the substructure, the quarks and gluons became the model of reality for elementary particles.
With the linear collider planned to explore the Higgs and the energy region above the higgs level, the limits on the size of the electron and the possible quark structure will be explored by deep inelastic scattering. I think it was Feynman who said : "to see what a watch is made out of one does not throw a watch on another watch, but one uses a screw driver" meaning electromagnetic and weak vertices which explored cleanly the substructure of the proton.
If the future higher energy deep inelastic data deviates from the standard model, this will trigger an interest in preon models. At the moment they are just mathematical games, or tools that might be needed when the time comes.
I am not very optimistic, because the point like nature of the electron is already very constrained,
Observation of a single electron in a Penning trap shows the upper limit of the particle's radius is 10^−22 meters
which means that any preons within it will need to have very high binding energy; , to see their effect as a hard core scatter will probably need much higher energies then the next generation leptonic colliders.
So the answer is that at present the standard model describes the data. New observations are necessary to justify adopting one of the preon models.
Relationship between electrons (leptons) and quarks
The problem you have here is that nobody has ever seen a free quark.
I assert the following is true: Either: electrons are made up of (two) quarks Or: Quarks are made up of some kind of smaller particles, which also make up electrons.
Neither are true. What is true is that you can make electrons and positrons out of photons in pair production. And then you can reverse the process and perform annihilation to get your photons back. What's also true is that you can do the same sort of thing for protons and antiprotons:
But we have no evidence whatsoever that electrons are made up of 2+ other particles, or that quarks are made up of 2+ other particles.
I think this must be the case because of the charge matching of electrons to protons, which dictates there must be some kind of kinship (or a coincidence of unfathomable proportions). Is this true?
There's a "kinship" of sorts. Ever looked at topological quantum field theory? It is related to, among other things, knot theory. And have you ever looked at a spinor, and compared it with the trivial knot? And have you ever looked at the next knot in the knot table, the treoil knot, and compared it to a proton?
Put your finger on the trefoil at the bottom left, then go round it anticlockwise calling out the crossing-over directions: up, down up. You've never seen a free quark because they are partons. They are parts of the whole, and they are not things that can exist singly. Electrons can. BY the way, none of these things are point-like. It's quantum field theory, not quantum point-particle theory. It's the wave nature of matter, not the point particle nature of matter.
