PieFed dev here.
PieFed is closer to Lemmy, yeah. Microblogs (i.e. the ability to follow mastodon profiles and have their posts show up in your timeline) are on the roadmap for this year.
Currently, Mastodon users can follow Piefed accounts and the posts from PieFed will show up in the Mastodon user's timeline. Those posts, viewed in mastodon, can be replied to there and the the reply will show up in PieFed. But not the other way around.