Bi-wire speakers and bi-wire cables?

listen to mijostyn on this

Yes, you can do it, but if you have decent jumpers like:
https://www.amazon.com/AudioQuest-Direct-Silver-Plated-BiWire-Jumpers/dp/B0057FK8RS/ref=sr_1_3?dchild=1&keywords=audioquest+jumper&qid=1597306205&sr=8-3
(they also come in gold plating)

then why do you want to change it?  Idea behind biwiring is that resistive and inductive impedance of the wire creates (with amp's output impedance) divider for back EMF, since crossover filter is not perfect (interaction between speakers).  I know, from this forum, that it helps with some speakers and makes absolutely no difference with the others.  It doesn't hurt to try.  I have three way speakers with jumpers between tweeters and mid range and shotgun cable connecting it and bass section to amplifier.

Just use one pair of the cables in the lower level binding posts with the jumper for single wire and remove the jumper and reinsert second pair of cables to the upper binding posts for bi-wire.  Differences tend to be hit or miss depending on speaker design, cables used, etc.  I’ll say from my experience a shotgun bi-wire cable sounds a little better than a single run I assume because the additional gauge further lowers resistance.  But, the difference is small enough that I’d advocate putting those $$$ into upgrading other components or interconnects, power cords, etc. before spending more on bi-wiring.  Of course YMMV.  I think ditching stock jumpers and replacing with better quality wire there may make a big improvement for much less $.  

One other further thing you can try is to continue to bi-wire while also using better wire jumpers simultaneously.  My cables use spade connectors but I also use wire jumpers in the banana connections and surprisingly it makes a significant improvement over just bi-wiring alone. FWIW. 

You can but it defeats the purpose of the experiment.  

Assuming that your speaker wires are of adequate gauge to begin with there is no advantage in bi wiring. 
Bass generally requires more current which requires thicker wire. It is actually better to run one low gauge wire than two higher gauge wires in regards to bass performance especially if you have low impedance speakers. The other way to deal with this is to use very short speaker wires. One three foot  wire is much better than two six foot wires. This is the advantage of using mono amps placed right behind the speakers.
The longer the wire the lower the gauge you need to use.
The best is short wires of low gauge. Bi wiring need not apply. 
In cases where the system has subwoofers a higher gauge for the satellites is satisfactory.