What beliefs would we consider reasonable for a self proclaimed Christian to hold?

[drfuzzy]

Three dimensional.  Our lives are three dimensional.  Our planet is three dimensional.  If there are other dimensions, we have no data on them, therefore, they are irrelevant.
Billions of people have come up with a god concept.  They were trying to explain what the sun was, or trying to control others by claiming that they could talk to the rain god.
Billions of people have come up with many thousands of very different gods.  It's called story-telling and imagination.  If there was any credible evidence of anything remotely like a deity, these "gods" would be identical, and proof for this creature would be obvious.  This is not the case.

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glob..
Our planet is 3 dimensional yes, but our existence is 4. The fourth being time. without the measure time the objects defined by the measure of length width and height are frozen in place. So again yes while science can indeed well define the objects found readily in the three dimensions it has no protocol to account for what s lost to time, besides guessing

Time.  Measured by our awareness as related to the earth's rotation.  So?  Time has no bearing on the existence or non-existence of any deities, and certainly provides no proof of the existence of such creatures.  And sure, we can say a lot about "what's lost to time" (lol) whole disciplines are built around it.  Time was once proposed as a 4th dimension but that was 100 years ago.  Here is a good article on the subject. 
  https://phys.org/news/2012-04-physicists...space.html     
“With clocks we measure the numerical order of motion in 3D space,” Sorli told Phys.org. “Time is 'separated' from space in a sense that time is not a fourth dimension of space. Instead, time as a numerical order of change exists in a 3D space. Our model on space and time is founded on measurement and corresponds better to physical reality.”