Joe, just to be clear: are you saying you believe that white has NO
first-turn advantage in Chieftain Chess, or are you saying that you believe
white has a first-turn advantage, but that it is SMALLER than the
first-turn advantage in FIDE Chess?
I think it is entirely plausible that weaker pieces will lead to a smaller
first-turn advantage, since the weaker your pieces, the less you can
accomplish each turn, and therefore the smaller the value of a turn.
But saying that there is NO first-turn advantage is equivalent to saying
that the null move, if it were allowed, would be the best possible opening
move. Do you recommend moving as few pieces as possible in the early part
of a Chieftain Chess game? Do you think that the best possible second move
is to reverse the move(s) made during your first turn? If not, it seems
unlikely that the null move is really optimal. Zugzwang certainly exists
in Chess, but it's pretty rare.
Also, your proposed "Moving 1 Square Chess" rules for knights appear to
boil down to "knights move as wazirs". You mandate changing parity every
move, but a wazir move changes color, so it will always change parity,
while a ferz move preserves color, so it will never change parity.