what are the best chemical raising agents to use in cakes that give the required fluffiness and a light texture? Also are there any replacements that could be used?
Sodium bicarbonate (Baking soda)
There are many different options that you can use. In my opinion the election of leavening agents depend on diverse aspects such as temperature, product, moisture, etc. For example, for sponge cake I use Sodium bicarbonate with SAPP (Pyrophosphate Sodium and Aluminium) but if you do not have SAAP you can use SAS (Sulfate of Sodium and Aluminium) or SALP (Phosphate of Sodium and Aluminium) or even I can make a combiantion between of Baking Soda with (MCPM) (Monocalcium Phosphate Mono hydrate).
In my humble opinion I would try to define % of baking soda of your product need and then try to use different leudants agents that could help you ( individually or mixed) the idea is try to develop your own baking powder according your requirements.
If any of this is unfamiliar to you, please let me know.