1) The map of Austro-Hungary. All Slavs of Upper Hungary were considered Slovaks. It's a very complicated question in fact, some of them in Spisz and Orawa spoke dialect closer to Polish, but in general, most accepted the nationality of the state they were given to after ww1, so most are indeed Slovaks now. Then it wasn't so sure.
The same goes for small Czadca region, which is south to Cieszyn Silesia. It was a disputed territory between Cieszyn Silesia and Hungary. Eventually it became Slovakia, and nowdays its population considers itself Slovakians, but it wasn't the case then: there were many highlanders from Czadca region that were settled in Bukowina region (nowdays Romania/Ukraine: that's the polish minority in Romania), and they considered and still consider themselves Poles. Slovakian is extremly similar to Polish, so you know, then the identity was very much blurred.
Germans in Cieszyn Silesia and Galicja (Galizien): the map is right at depicting german presence in Cieszyn Silesia, which amounted to 14% or so at the beginning of XX century. Bielsko city was majorly german, but apart from that, they were minority everywhere.
The map is wrong in depicting large german presence in Galicja, though. These lands were colonised by Germans in Middle Ages and further, my father's hometown allegedly among them. German nationalists, who seem to make these maps in Prussia, Austria etc, tend to paint these German communities as still existant then, but they were completely polonised in late XVIII century already, and so were some Austrian newcomers to Galicja.
The map, on another hand, shows no polish presence in eastern Galicja, and it was huge. City of Lwow itself, with its immediate surroundings, was majorly polish, as well as some areas around Tarnopol (Tarnopil). Most of the cities were polish-jewish, with few Ukrainians.
The map shows mountain Rusyns as Ukrainians, which is not completely obvious.
Czech Silesia: it's about right. I may add that the Czech bit east to the German line along Jesioniki and Odrzanskie mountains are Lach people. Their dialect is (was) sort of between polish and czech, and there were attempt of creating Lach language, which failed.
2) The "Voelkerkarte" is also faulty: German presence is underemphasised in Upper Silesia, while overemphasised in Pomerania. All the mixed polish-belarusian polish-ukrainian areas are shown as ukrainian and belarusian, respectively: bah, the language barrier according to this map goes even west to the initial polish-ruthenian border (which is the case in the mountains, due to vallachian settlement, but not elsewhere).
3) The first map is actually biased in favour of Poles when it comes to western Wołyń (Volhynia) and western Polesie... but it's biased against Poles when it comes to historical Lithuania, which is shown as Lithuanian / Belarusian, while it was, and partly still is, majorly polish. Lithuanians couldn't even dream of being so spread. In another words: this map is completely wrong and not even by some agenda or bias, but by sheer ignorance. Not to mention it shows Ukrainians and Belarusians as Russians.
To sum it up: these maps are very bad when it comes to polish matters.
this is a map for Cieszyn Silesia for the beginning of XX century
http://files.splinder.com/2ddafd06c01e19fdb38caf0448d27dd6.jpeg
(Germans are mostly in cities and in the less-polish areas in the east, that's the Bielsko exclave I've mentioned. Czechs, as I've mentioned, speak actually Lach dialect).
http://www.atlassen.info/atlassen/velhagen/andha06/picslarge/andha1914k047a.jpg
the ethnic map of Major Poland and Pomerania, 1910
http://upload.wikimedia.org/wikipedia/commons/c/c8/Ethnic_map_East_Prussia_1907.jpeg
that's the map for Prussia for 1900. However:
1) Germans were mostly in the towns, so their actual percentage in southern counties' population is actually larger than it may seem looking at this map
2) Most of this territory is Masuria (a bit around Allenstein/Olsztyn is catholic Ermland/Warmia, its borders are shown), which was majorly protestant, and while its people spoke polish, they didn't really feel much attachement for Poland.
http://upload.wikimedia.org/wikipedia/commons/c/cb/Polska1912.jpg
Poles 1912, this is based on official figures, so it's rather right when it comes to Germany (again, Masurians were polish-speaking but not polish-conscious), relatively right when it comes to Austria-Hungary, and completely wrong when it comes to russian part.
http://marcinimatylda.blox.pl/resource/05_07_07_mapa_wkl_23_najlepsza.jpg
this is a map of 1927, which shows the polish belt stretching from Poland proper to Latvia (russian censuses considered these Poles "catholic Belarusians", so they weren't visible in official data.
Its surprisingly accurate sometimes (see this little lithuanian bit under polish rule in the SE? That's actually the only majorly lithuanian place in Poland up to today. On another hand, it does seem aa bit too optimistic when it comes to Poles around Kowno / Kaunas. There were lots of Poles there, initially more than Lithuanians, there were majorly polish areas, but I'm not sure if SO many. But when it comes to lands further east, it should be right. In fact, there was some majorly polish area even further east which this map does not show, where there was a polish autonomous SSR in the middlewar period.
This belt, although much reduced after ww2 and repatriations, still partly exists:
http://envsec.grid.unep.ch/easteur/maps/envsec_eastern_europe20.jpg
http://upload.wikimedia.org/wikipedia/commons/8/84/Polacynagrodzienszczyznie.png
http://upload.wikimedia.org/wikipedia/commons/5/5e/Poles_in_Belarus_2009.PNG
http://www.flickr.com/photos/48544367@N08/4441683129/#/photos/48544367@N08/4441683129/lightbox/
http://upload.wikimedia.org/wikipedia/commons/5/5e/Poles_in_Belarus_2009.PNG
and a map of this belt from middlewar period:
http://www.halgal.com/graphics/PUR/PUR_map_mixethnic1.jpg
maps wiki has for interwar period are fine too:
http://upload.wikimedia.org/wikipedia/commons/6/60/Poland1937linguistic.jpg
http://upload.wikimedia.org/wikipedia/commons/7/72/Polacy_na_Kresach_1931.PNG
"jako najliczniejsza grupa gdy Ukraińcy i Rusini liczeni razem" - Poles are the biggest ethnic group, Ukrainians and Rusyns counted together".
http://upload.wikimedia.org/wikipedia/commons/2/25/GUS_languages1931_Poland.jpg
http://upload.wikimedia.org/wikiped...kerungsverteilung_Ostmitteleuropa_um_1918.jpg
To sum it up: the main difference between the maps and actual distribution of ethnicites in polish case is Russian Empire, which ignored the existance of the polish belt in middle Lithuania: also, Podlasie was is majorly polish (there are some majorly belarusian areas in Poland still
http://upload.wikimedia.org/wikipedia/commons/8/8b/Belarusians_in_Poland,_2002.png
but in general it's about that, whereas the line Grodno (Hrodna) - Wilno (Vilnius) - Dźwińsk (Daugvpilis) was majorly polish, and partly still is.
When it comes to Ukraine, there were many Ukrainians immidiately on the left bank of Bug/Buh river, and some Poles on the right one, but, in general, this was the border. definite polish majority area (+90%) ended west of San river, apart from the mountain areas, which were mostly Rusyn. On another hand, polish minority, slight majority and mixed areas stretched densely to polish pre-war border in Galicia (whe more south, the less Poles. There were milions of Poles living in other parts of Ukraine, but they were very much diffused elsewhere: in Volhynia, they were only a bit more than 10%, and further east - even less.