Masei: Did Joshua Add The Section About Arad and Chormah?

In sefer Yehoshua, perek 12, we read:

ז וְאֵלֶּה מַלְכֵי הָאָרֶץ אֲשֶׁר הִכָּה יְהוֹשֻׁעַ וּבְנֵי יִשְׂרָאֵל, בְּעֵבֶר הַיַּרְדֵּן יָמָּה, מִבַּעַל גָּד בְּבִקְעַת הַלְּבָנוֹן, וְעַד-הָהָר הֶחָלָק הָעֹלֶה שֵׂעִירָה; וַיִּתְּנָהּ יְהוֹשֻׁעַ לְשִׁבְטֵי יִשְׂרָאֵל, יְרֻשָּׁה--כְּמַחְלְקֹתָם.	7 And these are the kings of the land whom Joshua and the children of Israel smote beyond the Jordan westward, from Baal-gad in the valley of Lebanon even unto the bare mountain, that goeth up to Seir; and Joshua gave it unto the tribes of Israel for a possession according to their divisions;
ח בָּהָר וּבַשְּׁפֵלָה, וּבָעֲרָבָה וּבָאֲשֵׁדוֹת, וּבַמִּדְבָּר, וּבַנֶּגֶב--הַחִתִּי, הָאֱמֹרִי, וְהַכְּנַעֲנִי הַפְּרִזִּי, הַחִוִּי וְהַיְבוּסִי. {ש}	8 in the hill-country, and in the Lowland, and in the Arabah, and in the slopes, and in the wilderness, and in the South; the Hittite, the Amorite, and the Canaanite, the Perizzite, the Hivite, and the Jebusite: {P}
ט מֶלֶךְ יְרִיחוֹ, {ס} אֶחָד; {ס} מֶלֶךְ הָעַי אֲשֶׁר-מִצַּד בֵּית-אֵל, אֶחָד. {ר}	9 the king of Jericho, one; the king of Ai, which is beside Beth-el, one;
י מֶלֶךְ יְרוּשָׁלִַם {ס} אֶחָד, {ס} מֶלֶךְ חֶבְרוֹן {ס} אֶחָד. {ר}	10 the king of Jerusalem, one; the king of Hebron, one;
יא מֶלֶךְ יַרְמוּת {ס} אֶחָד, {ס} מֶלֶךְ לָכִישׁ {ס} אֶחָד. {ר}	11 the king of Jarmuth, one; the king of Lachish, one;
יב מֶלֶךְ עֶגְלוֹן {ס} אֶחָד, {ס} מֶלֶךְ גֶּזֶר {ס} אֶחָד. {ר}	12 the king of Eglon, one; the king of Gezer, one;
יג מֶלֶךְ דְּבִר {ס} אֶחָד, {ס} מֶלֶךְ גֶּדֶר {ס} אֶחָד. {ר}	13 the king of Debir, one; the king of Geder, one;
יד מֶלֶךְ חָרְמָה {ס} אֶחָד, {ס} מֶלֶךְ עֲרָד {ס} אֶחָד. {ר}	14 the king of Hormah, one; the king of Arad, one;
טו מֶלֶךְ לִבְנָה {ס} אֶחָד, {ס} מֶלֶךְ עֲדֻלָּם {ס} אֶחָד. {ר}	15 the king of Libnah, one; the king of Adullam, one;
טז מֶלֶךְ מַקֵּדָה {ס} אֶחָד, {ס} מֶלֶךְ בֵּית-אֵל {ס} אֶחָד. {ר}	16 the king of Makkedah, one; the king of Beth-el, one;
יז מֶלֶךְ תַּפּוּחַ {ס} אֶחָד, {ס} מֶלֶךְ חֵפֶר {ס} אֶחָד. {ר}	17 the king of Tappuah, one; the king of Hepher, one;
יח מֶלֶךְ אֲפֵק {ס} אֶחָד, {ס} מֶלֶךְ לַשָּׁרוֹן {ס} אֶחָד. {ר}	18 the king of Aphek, one; the king of the Sharon, one;
יט מֶלֶךְ מָדוֹן {ס} אֶחָד, {ס} מֶלֶךְ חָצוֹר {ס} אֶחָד. {ר}	19 the king of Madon, one; the king of Hazor, one;
כ מֶלֶךְ שִׁמְרוֹן מְרֹאון {ס} אֶחָד, {ס} מֶלֶךְ אַכְשָׁף {ס} אֶחָד. {ר}	20 the king of Shimron-meron, one; the king of Achshaph, one;
כא מֶלֶךְ תַּעְנַךְ {ס} אֶחָד, {ס} מֶלֶךְ מְגִדּוֹ {ס} אֶחָד. {ר}	21 the king of Taanach, one; the king of Megiddo, one;
כב מֶלֶךְ קֶדֶשׁ {ס} אֶחָד, {ס} מֶלֶךְ-יָקְנְעָם לַכַּרְמֶל {ס} אֶחָד. {ר}	22 the king of Kedesh, one; the king of Jokneam in Carmel, one;
כג מֶלֶךְ דּוֹר לְנָפַת דּוֹר, {ס} אֶחָד; {ס} מֶלֶךְ-גּוֹיִם לְגִלְגָּל, {ס} אֶחָד. {ר}	23 the king of Dor in the region of Dor, one; the king of Goiim in the Gilgal, one;
כד מֶלֶךְ תִּרְצָה, {ס} אֶחָד; {ס} כָּל-מְלָכִים, שְׁלֹשִׁים {ס} וְאֶחָד. {ר} {ש}	24 the king of Tirzah, one. All the kings thirty and one. {P}

Pasuk 14 is troubling, for it states "the king of Hormah, one; the king of Arad, one." But in parshat Masei, we see a king of Arad, who is a Canaanite. In Bemidbar 33:

מ וַיִּשְׁמַע, הַכְּנַעֲנִי מֶלֶךְ עֲרָד, וְהוּא-יֹשֵׁב בַּנֶּגֶב, בְּאֶרֶץ כְּנָעַן--בְּבֹא, בְּנֵי יִשְׂרָאֵל.

40 And the Canaanite, the king of Arad, who dwelt in the South in the land of Canaan, heard of the coming of the children of Israel.--

And in the earlier accounting of this, in parshat Chukat, not only do we have Arad, but Chormah as well:

א וַיִּשְׁמַע הַכְּנַעֲנִי מֶלֶךְ-עֲרָד, יֹשֵׁב הַנֶּגֶב, כִּי בָּא יִשְׂרָאֵל, דֶּרֶךְ הָאֲתָרִים; וַיִּלָּחֶם, בְּיִשְׂרָאֵל, וַיִּשְׁבְּ מִמֶּנּוּ, שֶׁבִי.	1 And the Canaanite, the king of Arad, who dwelt in the South, heard tell that Israel came by the way of Atharim; and he fought against Israel, and took some of them captive.
ב וַיִּדַּר יִשְׂרָאֵל נֶדֶר לַיהוָה, וַיֹּאמַר: אִם-נָתֹן תִּתֵּן אֶת-הָעָם הַזֶּה, בְּיָדִי--וְהַחֲרַמְתִּי, אֶת-עָרֵיהֶם.	2 And Israel vowed a vow unto the LORD, and said: 'If Thou wilt indeed deliver this people into my hand, then I will utterly destroy their cities.'
ג וַיִּשְׁמַע יְהוָה בְּקוֹל יִשְׂרָאֵל, וַיִּתֵּן אֶת-הַכְּנַעֲנִי, וַיַּחֲרֵם אֶתְהֶם, וְאֶת-עָרֵיהֶם; וַיִּקְרָא שֵׁם-הַמָּקוֹם, חָרְמָה. {פ}	3 And the LORD hearkened to the voice of Israel, and delivered up the Canaanites; and they utterly destroyed them and their cities; and the name of the place was called Hormah. {P}
ד וַיִּסְעוּ מֵהֹר הָהָר, דֶּרֶךְ יַם-סוּף, לִסְבֹב, אֶת-אֶרֶץ אֱדוֹם; וַתִּקְצַר נֶפֶשׁ-הָעָם, בַּדָּרֶךְ.	4 And they journeyed from mount Hor by the way to the Red Sea, to compass the land of Edom; and the soul of the people became impatient because of the way.

Though the text in context, in pasuk 4 places this by Hor HaHar. On the other hand, this whole section might be read as insertion, in which case pasuk 4 tells us nothing.

Is it possible that this is a late insertion into the Torah by Yehoshua, of his own battle?

Ibn Ezra addresses this:

וישמע הכנעני מלך ערד -
אמרו הקדמונים:
שהוא סיחון ונקרא הכנעני כי כל אמורי כנעני.

ורבים אמרו:
כי זאת הפרשה יהושע כתבה והראיה מלך ערד אחד ומצאו שבני יהודה קראו שם המקום חרמה, ולא אמרו כלום כי אותו המקום יקרא בתחלה צפת וזה מלך ערד והאמת שני מקומות ורבים במקרא כמו הם ומלך ערד על פשוטו הוא מעבר לירדן מזרחה ונסמכה זאת הפרשה למות אהרן כי הכתוב ספר מה שאירע בהר ההר קודם נסעם משם והעד: וישמע הכנעני מלך ערד ואחריו ויסעו מהר ההר ואם תבקש מה שמע הנה מפורש.

I don't know who these "many" are, who say this. But why say this, that that place in sefer Yehoshua, in Tzfas (Sefad)? Because there is another pasuk, and another place, called Chormah. In Shofetim 1:17:

יז וַיֵּלֶךְ יְהוּדָה, אֶת-שִׁמְעוֹן אָחִיו, וַיַּכּוּ, אֶת-הַכְּנַעֲנִי יוֹשֵׁב צְפַת; וַיַּחֲרִימוּ אוֹתָהּ, וַיִּקְרָא אֶת-שֵׁם-הָעִיר חָרְמָה.

17 And Judah went with Simeon his brother, and they smote the Canaanites that inhabited Zephath, and utterly destroyed it. And the name of the city was called Hormah.

Shadal's take on this, in parshas Chukas, is as follows:

נראה כי המאורע הזה איננו אותו שבשופטים (א י"ז), אלא עכשו לקחו קצת מעריהם והשאר בימי יהושע.

I am not 100% certain of the point he is making here. Thus, it would appear that at the least, he does not equate the one in Tzfas to the one in Chukas and Masei. This is one point Ibn Ezra makes, though Ibn Ezra equates the cities in Yehoshua with the cities in Shofetim.

But by saying that now they took some of their cities and the others in the days of Yehoshua, he seems to me to be saying (though I could be wrong) that this is indeed the one mentioned in sefer Yehoshua. Except that it happened earlier, in Penteteuchal times, and just happened to be listed among other cities in sefer Yehoshua, which happened in post-Penteteuchal times, that is only in the days of Yehoshua.