As for retrieving blog entries and comments APIs - Retrieving blog posts and Retrieving a blog comment, there are common filters support for ideas and ideas' comments.
Add below filters as input query parameters.
graduated ideas only (=graduated)
active ideas only (=active)
default is all (=all)
date (published timestamp)
title (entry title)
votes (# of votes)
comments (# of comments)
visits (# of visits)
by creator (firstname.lastname@example.org)
by external id (userid=4fda6cc0-0101-102e-88de-f78755f7e0ed)
Retrieving blog posts ic45
Retrieving a blog comment ic45