Specific reduction of certain functional groups
1.The selective reduction of the carboxylic group is explained in this article. Link:https://www.ch.imperial.ac.uk/rzepa/blog/?p=5114. It could reduce esters but is not favourable at all and difficult.So if u only have an ester grp and its treated with bh3, then you can reduce it. However if both carboxylic and ester grps are present, carboxylic acid gets reduced .


Regarding reduction with h2/pt and h2/pd-c not much can be said. The thing is at higher temperatures and pressures(extreme conditions)both could reduce esters. Generally esters are NOT reduced via cataytic hydrogenation (it is just not favourable).However reduction has been performed in mild conditions via other complexes like ruthenium.(https://pubs.acs.org/doi/pdfplus/10.1021/op4003278