According to the press release of the city of Yokohama, the twins were born to Sumatran tigers Guntur and Deru of Zoorasia.
The southwestern corner of the Nogeyama is closed off for renovation. This means that Nakayoshi Square, housing guinea pigs and mice is closed off (they can be seen near the fish house I believe). Unfortunately, this also means humboldt penguins, swamp wallabies and the only kagus in Japan cannot be seen.
I see a 1/4 portion cordonned off as grey space. They provisionally - I suspect - have rehoused red panda to near the lions in the NE corner of Nogeyama Zoo. SOURCE: https://www.hama-midorinokyokai.or.jp/zoo/nogeyama/map.php
Information on non-exhibited animals and park road closures due to renovation work|Notice|Nogeyama Zoo official website|Yokohama City Green Association (hama-midorinokyokai.or.jp) Hope the reconstruction message is a typo.
