Syntax-wise, it's a single compound subject, united by a conjunction.... but in such cases Russian allows variation (i.e. agreement with the first member or with the entire subject) ....
Yes, approximately this is the case also in Slovak, but the agreement with the first member occurs rather in the colloquial speech, at least I think so ...
kde parkuje autobus a [kde parkujú] taxíky ...
"Kde parkuje autobus a kde parkujú taxíky?" is grammatically surely the best solution.
1. Kde parkuje autobus a taxíky?
It is possible and used. However, for me it does not sound very well, I'd prefer the plural
"Kde parkujú autobus a taxíky?" ...
2. … ale radšej živé ako umelú reč.
Without any context, it is not correct. The problem is that the adjective "živé" here seems to refer to "umelú reč", which would be obviously ungrammatical.
It should be "radšej živé reči ako umelú reč". In this case we simply compare two things, independently if they are in singular or plural.
Ja sa tiež učím cudzie jazyky, ale radšej živé ako umelú reč.
This is possible because "živé" is spontaneously related to "cudzie (reči)".
“Jazykom/-mi rozoznávame chuť sladkú, kyslú, horkú, slanú, trpkú.”
Here "jazykom" is better then "jazykmi", as normally one has an only tongue ...
Your sentence is possible. But strictly speaking, I'd prefer the following versions:
"Jazykom rozoznávame
chute: sladkú, kyslú, horkú, slanú, trpkú".
"Jazykom rozoznávame sladkú, kyslú, horkú, slanú a trpkú
chuť".
What's bothering me is that Hungarian adjectives not only have no agreement with the head nouns, but also start to function as nouns themselves when there's no overt head noun (seizing all the noun affixes in particular). I'm not sure that could count as normal ellipsis of the head nouns at all, which might also explain the syntactical differences.
Withou entering into details, the Hungarian (aglutinative) logic is surely different from the Indo-European. The substance is that the basic (unmarked) forms of words tend to be "neutral" from the grammatical point of view. The consequenses are that the so called "case endings" and the plural marker appear only once, at the end of the word or a complex construction, there is no formal difference between nouns and adjectives, there is no agreement, often the singular is used when in IE languages the plural is needed, etc....