天業恢弘 tengyo kaiko (extending the destined work)
This phrase was based on Nihon Shoki, a legendary history book. The first emperor Jinmu proposed his princes to expand his territory to the east and this phrase (slightly different) appeared in his speech.http://en.wikipedia.org/wiki/Nihon_Shoki
This word was sometimes used by militarymen & nationalist referring to the emperor's war. Here this slogan sounds 'Help the emperor's work (to expand the imperium)!'
The encircled horizontal chars reads 祝入営湯浅一男君 (Congratulations for mobilization, Mr. Yuasa(湯浅) Kazuo(一男)). 君(kun) is a wording to a junior or mate. Some signs have the same family name 湯浅.
神光 shinko = holy light
I have not seen any militaryman's flag indicationg his destination. Perhaps it was not allowed to carry on for security reason. And usually families did not know where the soldier was fighting.
陸軍曹長勲七等(award 7th grade, army master seageant)新井国松
曹長 (socho, master seageant) was used until 1932 so 新井国松 (Arai Kunimatsu) was an old veteran. In Japanese system individual achievement was seldom awarded by decoration and instead militarymen got awards roughly according to their rank.
陸軍主計少尉 従八位 加藤? (army accounting 2nd lieutenant, lower 8th class, Kato?)
In right above an accounting officer signed. 位 roughly corresponds to his 等 but not to the same number. lower 8th class was common for 2nd lieutenant and perhaps he was award 6th grade.