Manžel was malžen in Old Czech and manželka was malžena (but rarely, the switch happened quite early). Originally malъženъ in Common Slavic was man and a women together, but the meaning of the mal is unclear. It may come from Germanic or from mladý.

BTW, the Vasmer's dictionary says Old Polish had manżel.

BTW, the nasal in mąż is connected to the original nasal in the Proto-Slavic mǫžь which originates in mon- which is cognate to English man. Basically, that Slavic nasals were the result of the law of open syllables in the classical stage of Proto-Slavic and originate from an actual n consonant.

The ǫ then later denasalized into u or ú in the individual Slavic languages (at least in the northern branches) so we have muž in Czech while Polish retained mąż (the details are more complex).

Basically, Polish ę most corresponds to Russian ja and in Czech most often to e or ě, but also á or even í. pięć vs. pět, część vs. část

Polish ą mostly corresponds to Czech u or ú(->ou). pająk vs. pavouk (Old Czech and current Slovak pavúk)

But sometimes the Polish nasals switched from one nasal to the other: będę vs. budu (Proto-Slavic bǫdǫ).

Yes, it is fine. There are many word orders depending on what the topic and the comment of the sentence is https://en.wikipedia.org/wiki/Topic_and_comment

And you must keep clitics in the second position. And certain words can be either in the second position as clitics or in the strong position at the start or at the end.

This is really the same as "Jaký je František manžel?".