Once again, I searched through the archives of the Berlin Senate and came across some interesting information:
Document 1 (pages 215 + 217) concerning GRW funds (GRW means something like common mission of funding the local economy including touristic structures):
https://www.parlament-berlin.de/ados/19/WiEnBe/vorgang/web19-0154-01-v.pdf
GRW funds for 2022:
projects across different areas (savannah?): 7,146,543.81 euros
Pachyderm house: 0 euros
GRW funds for 2023:
projects across different areas (savannah?): 3.700.000 euros
Pachyderm house: 679,131.56 euros
GRW funds for 2024:
projects across different areas (???): 2,927,700.00 euros
Pachyderm house: 9,000,000.00 euros
GRW funds for 2025:
projects across different areas (???): 2,700,020.70 euros
Pachyderm house: 14,609,577.95 euros
This means that the Pachyderm House will (hopefully!) finally get underway next year, although most of the money will not be spent in 2025. However, I don't quite understand the "projects across different areas" for 2024 and 2025 (totalling almost 6 million euros). It's a shame that there are no more details! According to current planning, however, it should actually be something for Africa again.
Speaking of Africa: Now to document 2 (here it's page 7 of 7)
https://www.parlament-berlin.de/adosservice/19/Haupt/vorgang/h19-1206-v.pdf
This is not about GRW funds, but about the so-called Innovation Promotion Fund IFF, a pot totalling 750 million as of 2023. And here, too, the Tierpark has apparently secured funds, namely a share of 3 million (out of a total of 5 million budgeted) for the "Species conservation project "Breeding station for northern white rhinoceros" at Friedrichsfelde Zoo"! Planned funding: 1 million out of 1.8 million budgeted for 2024 and 2 million out of 2.755 million budgeted for 2025! So not only is it finally clear which rhinos are being planned for, but this project should actually even start very soon! This also confirms my suspicion that the unlabeled GRW funds are also planned for Africa (e.g. the outstanding funds for the rhinos or funds for the lions, etc.).
So 2024 could once again be a very exciting year and 2025, or perhaps 2026 should hopefully be a very joyful year with great new animals arriving and important new exhibits opening. It also seems like they are really doing an amazing job at securing funds now.