The white one may be some weevil. It damages the leaves of some plants.
The brown one is the culprit that cuts down new reddish leaves of mango...
Which ones are these pests?
A white, another brown beetle
The first image is of a weevil in the subfamily Entiminae (short-snouted/broad-nosed weevils). This is a very large group containing many species that can appear quite similar in overall appearance; I would not be at all confident about attempting a more specific identification. Here’s one example, Myllocerus viridanus - https://www.projectnoah.org/spottings/1043956004
The other two images are of another very large family, leaf beetles (family Chrysomelidae). The brown one bears a close resemblance to Aulacophora foveicollis, known as the red pumpkin beetle – see https://www.plantwise.org/KnowledgeBank/pmdg/20177801271 However, that species reportedly feeds only on members of the squash/gourd family. The paler one resembles some species in the genus Lema, well over100 species in this genus have been reported from India – see http://faunaofindia.nic.in/PDFVolumes/records/078/01-04/0041-0061.pdf
Indeed, Flap. But you linked a good image, so very close.
The red one, I've captured here are in fact on the bottle gourd leaf and you are right. Thd one on the mango lieaf I mentioned has slightly different shade. Will try to get.
It's Deporaus marginatus, known strangely enough as the mango leaf-cutting weevil!