Can Interconnects be converted to speaker cables

I agree with Alexs. Most (not all) interconnects are typically less than 20 gauge. Interconnects run a very low voltage and current where speakers require a LOT more current. That is why you would want a heavier gauge for the speakers.

no no and no don't even think about it
the impedance characteristics alone make this an exercise in futility

Morrow Audio cables, at least the early ones (I don't know about current versions), used the same thin solid core wire for both ICs and speaker cables, just a few more strands for the speaker cables. I'm still using them in both roles and like them a lot. Many speaker cable users employ quite thin wires very successfully.

Yes it can be done, but is will sound terrible. Each strand or wire should match and that is not the way IC's are made.
But in honesty the signal can be sent across most conductive material. You have only to lose and nothing to gain.

Many speaker cable users employ quite thin wires very successfully.

Yes that is true but usually many wires. My Nordost frey speaker cables use 28 24 gauge wires where the ics use 6 26 gauge wires. Capacitance and inductance is quite different too.