Marco Leon wrote:

3) Again, if yes, how critical is it to keep the 496 up to
date with the same database? Will it behave badly if it
is not in sync and there is a renamed fix in the active
plan? I plan on updating the 496 only once or twice per
year while I have the 430 on the IFR-mandated 28-day
cycle (OK guys, don't get hung up on the term
"mandated"--you know what I mean).

I have my 496 fed from either my KLN-94 or my KLN-90B, and the
databases are way out of sync. It works fine. The 496 will create a fix
if it has to, and it's position is different from that in the data from
the IFR unit, you just end up with an aliased user waypoint, offset
slightly from the 496's version.