Why not "estas malproksime de"?
Am I the only person who constantly mixes up "domo" and "hejmo"?
Nope. I messed that up many, many times. I've finally started to get it together.
why not "el" ?
el = out of
You probably meant "al" (in the direction of)
I was wondering the same, but going by the example sentences on Vortaro.net, it seems both "(mal)proksima de" and "(mal)proksima al" have been used by Zamenhof.
What is difference in meaning beween "La preĝejo estas malproksima de nia domo." and "La preĝejo estas for de nia domo"?
I picked "for" because it's less typing.
I think "malproksima" is more about the (long) distance, whereas "for" also has the connotation of not being accessable.
Why would "je" not work here?
What is the difference between preĝejo and kirko? Do they both mean "church"?
"Kirko" is the Esperanto word for "kite" (the bird, not the thing you fly on the end of a piece of string). "Church" is either "preĝejo" (the building) or "eklezio" (the people).