Yes, non-Orthodox Jews can become Orthodox by becoming more observant. Non-Jews can become Orthodox Jews through Orthodox conversion.
Orthodox Jews are strictly observant. Hassidic Jews are even more strict.
No, Torah-observant Jews do not.
Observant Jews do not eat crayfish.
The majority of observant and semi-observant Jews practice their religion everywhere they go, during all their waking hours.
Observant Jews say the Shema twice a day.
Yes. Torah-observant Jews will make sure that the ingredients are kosher.
Religiously observant Jews will only eat foods that are kosher.
I don't believe there is a real way to answer this question. I think it is completely dependent on where you live in the world and how observant you are.
Yes, Jews can eat chicken. Religiously observant Jews would require that the chicken be kosher.
A realtor can use a Shabbat elevator as a selling point for Orthodox Jews. I don't know of any non-observant Jews who would be discouraged from buying because of this though.
Religiously observant Jews will only eat in restaurants that are kosher certified.