Who is "Lo Yeishvu be'Artz'cha referring to?
Gitin, 45a: It is referring to Cana'anim who persist in worshipping Avodah Zarah, but to those who undertake to desist from doing so. 1
Gitin (Ibid.): As is evident from the Pasuk in Ki Seitzei, 23:16 - in connection with an Eved Cana'ani who rins away from his master "Lo Sasgir Eved el Adonav".
What are the connotations of "Ki Yih'yeh l'cha la'Mokesh"?
Rashi (in Teshuvos): It means 'Lest they ensnare you'.
Refer to 23:33:1:1-2.
Oznayim la'Torah: A Mokesh (a snare) is innocent-looking from the outside, but it causes havoc and destruction, so too one initially thinks what can be wrong with paying allegience to the sun and moon
How does the phrase "Ki Yih'yeh L'cha le'Mokesh" fit into the Pasuk?
Rashi: It follows the previous phrase - ' ... when you worship their gods which will ensnare you'.
Ramban and Seforno: The (inverted) Pasuk reads 'They shall not dwell in your land, because they will be for a trap, lest they cause you to sin, when you worship their gods'.
Targum Onkelos and Targum Yonasan: '... because you will worship their gods, because they will be a trap for you'.
Moshav Zekenim: This is right before "Aleh El Hashem... Nadav va'Avihu", for it was a pitfall for them that they saw the Shechinah (Nadav and Avihu died due to this).