Rulings
Q1: What is the effect of "opponent cannot add memory outside of tamer effects"?
OPPonent is an effect that prevents all effects from adding memory except for the tamer effect. This effect affects the opponent player.
Q2: When "BT17-087 Daimon Dai" which is treated as Digimon is rested while "opponent cannot add memory except by tamer effect" effect of opponent is activated, can't All Turns effect of "BT17-087 Daimon Dai" Can't I add memory?
No, memory can be added. The effect activated by a card treated as both Digimon and tamer includes both Digimon's effect and tamer's effect, so memory can be added.
Data Sources
A
Official English (Asia) Card Listen.digimoncard.com
Lv.3 Shamanmon BT18-009 C Rookie | Virus | Demon [All Turns] Your opponent can't gain memory other than by Tamer effects.
W
DCG Wikidigimoncardgame.fandom.com
Lv.3 Shamanmon BT18-009 C Rookie | Virus | Demon [All Turns] Your opponent can't gain memory except with Tamer effects.
JP
Official Japanese Card Listdigimoncard.com
Lv.3 シャーマモン BT18-009 C 成長期 | ウィルス種 | 鬼人型 【お互いのターン】相手はテイマーの効果以外でメモリーをプラスできない。