From what I've seen from the screenshots, some of the characters we'll be getting on V4 include the following:
~Mametchi, Memetchi, and Kutchipatchi (as usual)
~MohiTamatchi and MizuTamatchi (returning from V3)
~PetitChocotchi (From Osu/Mesu, panda-ish child characher from TMP2)
~Harutchi (From Osu/Mesu, blue Mametchi child from TMP4)
~Hawaikotchi (From Mesu, tooth-shapped teen with pink pigtails, TMP1)
~Ojitchi, Otokitchi, and Oyajitchi (as usual)
New items include
~Toy Helicopter
~Piano
~Sound System
~Jeans
Features carried over from Entama seem to include:
~Ball-antenna shell
~Highest amount of points possible increased (about 99,999G)
More info to come as more Jinsei (V4) info is revealed.