GBA is probably ruled out because with Fusion, at least, Nintendo gave an announcement the week prior, but there's no set pattern yet.
GB I think is likelier, I think, purely because the base subscription hasn't had any retro games this month, but I wouldn't count on the Oracle games being next - it could well just be a slightly random pair of games.
This is a pretty good selection, anyway. Pulseman especially is intriguing.
Edit - tbf, I don't think we have enough info yet to really know how Nintendo will pace NSO titles now the GB family is present across two tiers. I'd just err on the side of caution and assume they'll continue to be quite slow.