The characters look very similar to Jindai moji (Encyclopedia of Shinto link) (Japanese Wikipedia link).
(Image taken from Talk:Jindai moji page on Wikipedia)
These characters are theorized to have been Japan's character system before Chinese characters were introduced.
If I go through that table for the first image you show and match the characters (with help from the matching done by the article that @senshin posted), that gives me
ツ(tsu) ヰ(wi) ヲ(wo) ソ(so) マ(ma) ? カ(ka) 〜 エ(e)
ノ(no) ゴ(go) ト(to) ハ(ha) ア(a) ク(ku) テ(te) ロ(ro) コ(ko)
エ(r) タ(ta) ナ(na) ソ(so) ル(ru) イ(i) ア(a) シ(shi) サ(sa)
サ(sa) メ(me) ゴ(go) ハ(ha) ク(ku) ロ(ro) フ(fu) ツ(tsu) ヲ(wo)
リ(ri) ヰ(wi) ソ(so) ? 〜 ミ(mi) ス(su) ウ(u) ガ(gu)
My Japanese is not very strong, but I don't get any relevant results when looking any consecutive substrings of those characters up on Jisho (a Japanese-English online dictionary) or Google Translate.
I don't believe that the characters have any special meaning here.