When using emitter follower for the gate driver can i guarantee a FET with a 1.4V minimum Gate Threshold will fully turn off from the 0.7V emitter follower output low?
Yes, it's fine. It'll be a little slow getting there, perhaps, but that's fine (as I recall, preferable even, for your application?).
Ok, Have updated to emitter follower.
There are no base/emitter protection diodes, are they needed for this sort of configuration, or are the 1k resistors enough for protection?
Correct, no need. Also don't need the base resistors. The gate resistors handle that, and more accurately (and, individually besides!). Which since you're not doing much current here anyway, those should probably be more like 100R or something?
Q28 would be better as an NPN with emitter resistor, so that it drops the voltage instead of R212, and less voltage swing --> slightly faster switching. R525 can then be much smaller, to the same end.
Note that Q142 etc. can turn on pretty hard, making Q21 not very useful: if that's the case, then replace it with a diode. Then you just have boosted pull-down (R354), which makes sense, a resistor is gonna suck.
R58 and D13 aren't needed. Make 24V_Boosted relative to source, or Batt_12V, to avoid overvolting the gates if that's the concern.
Also, check R202 vs. R202.
Tim