Here's a related question - Can Void shields be removed as hack-down kills?

Q: Does AP fire take down a Void Shield?
A: No. Only AT, MW or TK fire can affect a Void Shield. Note that FF attacks in an Assault will damage a Titan’s Void Shields. Also remember that the Titan or WE will also receive a Blast marker for coming under fire even if it can’t affect the Titan or damage its Void Shield

Are there any non-fearless units with shields?

No, the FAQ on what can damage a void shield does not state hackdowns.
Also most of the units/WE's that do have Void shields are Fearless so would not take hackdowns anyway.

3.3.3 Result Rolls
When working out the result of an assault that includes a war
engine, count each point of damage inflicted on a war engine as
a ‘casualty’. Each surviving war engine counts as a number of
units equal to its starting damage capacity when working out if
one side outnumbers the other. If a war engine loses an assault,
then it takes one extra point of damage for each point it lost the
assault by. Roll for critical hits normally.

A broken war engine is assumed to have a number of Blast
markers equal to its starting damage capacity for all rules
purposes. If there are any enemy units within 15cms of the war
engine after it makes a withdrawal then it suffers one extra
point of damage (no save allowed) for each enemy unit that is
within 15cms. Additional hits caused by losing an assault or
receiving Blast markers while broken cause one point of
damage each. Roll for critical hits from these extra hits as you
would normally.