Help With Some Maine And ?maryland Precancels, Please?

The three on the left are from Maine and I just can't read them. I know it's a long shot but can anyone make anything out?

The three on the right, I acquired with a collection of Maryland stamps, but they make no sense.

a) The 2c Prexie seems pretty clearly to say Big Pool, but there is no such (precancel) town anywhere in the US. The State could say MD or MO, but that is not helping me. Not a precancel?

b) The Falmouth Heights one should be from MA. That's the only FH in the country, but the state is clearly NOT "MA". Printing error????

c) The Sparks one - yes, there's a Sparks, MD, but it only has a Type 745 which looks absolutely nothing whatsoever like this. Box cancel? Or?

Thanks.

Sparks MD: https://en.wikipedia.org/wiki/Sparks,_Maryland

Falmouth Heights is probably MA

Towns in Maine that start with "C" ... take your pick: http://docs.unh.edu/towns/MaineTownList.htm

I am guessing the first MD is Aberdeen Proving Grounds,... but hard to tell.

The first example I would guess to be Clinton, ME (Type 703).

The last is correct as a Sparks, MD precancel(Type 743).

The Falmouth Heights, "MD" precancel is likely Falmouth Heights, "MA" (Type 749). There are some obscure references on the internet suggesting that there is a known typographical error in the State name erroneously replacing "MD" for "MA".

Big Pool MD is listed as a fake in the Cummings fakes catalog.
Falmouth Heights MASS has an error making the state MD, it is PSS listed at 0.25
Sparks MD is not 743, it is listed in Cummings as a postcanceller.

first Maine not Clinton 703, I dunno
second Maine, probably Clinton 703
third Maine, dunno

Thanks so much -- for the first Maine one, my best guess is a Houlton of some sort? With the rounded letter at right (C / O) being so close to (but just slightly to the left of) the cut-off "M" underneath, it looks like a word of a couple more letters than just the 5 letters of Maine.

So I was thinking there could be a missing letter "H" at right, before the C/O. Maybe a type 703?

Does anyone know if there are Houlton bicentennials with a 703 on them?