Dative preposition = in/im

I understand that “im” is a contraction for “in dem” which means you can write a sentence like “He is in the car” like “Er ist im Auto”, as an alternative to “Er ist in dem Auto”, which is easier way to apply the preposition “in” in the dative case form.

1. Can you do something similar with “der / masculine form”? e.g.
English: He is in the bus
German: Er ist in dem Bus -> Is the contraction the same? im?
 
2. Can you do something similar with “die / feminine form”? e.g.
English: It is in the box
German: Es ist in der Kiste - > Is there any contraction possibility here?
 
3. Any contraction for “plural form”?

Hallo RexV!

The answer to this question is the same as the answer to your previous one:

In + dem will always contract to im, whether dem is masculine or neuter - so yes, this is definitely possible!

There aren't any contractions between in and der or den, however, so none for the feminine or plural forms.

Be sure to keep in mind that the contraction im for in + dem is standard, so Er ist im Auto shouldn't really be thought of as an alternative to "Er ist in dem Auto"; rather, it is the preferred form (unless, as we've said before, dem is being emphasized for some reason). 

Tschüss!

Liss