Is it ever unsafe to compress an EC point? I am working with a library that outputs EC points in uncompressed form.  To save space, I'm considering modifying said library to use compressed EC points.  Assuming that I keep track of the sign bit prior to compression, is there any risk in compressing said point? 

I read this Q and related answer, but want to ensure that I may not be opening the door for other issues.
I would argue the opposite: it's safer to compress a point.   

The reason is fairly simple.   During decompression- whose most expensive operation is a modular square root - your are guaranteeing that the resulting point either is on the curve, zero or infinity.   

One of the most frequent errors in elliptic curve operations is failing to properly validate a point before operating on it.   The most public example of this is the Bluetooth pairing vulnerability - which, had it used compressed points, would not have been vulnerable to MITM attacks.

While validation is less expensive than decompression - it's one of those "seemingly optional" steps that people can forget to do.   With compressed points there's no option.