I dare say most of the entries on the mea culpa lists are perfectly fine as singular vehicle names . Some are in common usage
Marquis is a variant of marquess and is singular. Others may have been brought over inaccurately to English and have a long history of misuse in English so that tradition can not be bucked. Lynx might fall into that category, but I don?t think so. Our plural is lynxes. It appears to be from Greek and making it plural seems accurate. impalas is the accepted plural of impala.
What is the singular of Cheyenne, Navajo, and Comanche? Gemini refers to a constellation so that is fine, though a stupid name for a vehicle that seats more or less than two.
BTW, I think that should be ?two Barracudas hemi? in the proposed song. That is especially so since you can?t really have two hemispheres since that would be a sphere. Polysphere, O.K., that has a special meaning outside of internal combustion engines.