Multiple features are normally developed in parallel. It's good practice to keep up to date with the latest develop/master to avoid surprises at later stages.

Rebasing your work onto the head of master before merging it in, versus cherry-picking the relevant changes from your branch onto the head of master, are perfectly identical in terms of end result - whichever workflow is easier for you will achieve the same thing.

And of course you can get conflicts if multiple people are developing over the same files - this will happen regardless of using merge, rebase, or cherry pick (or even patches over email). You fix the conflicts when merging / rebasing / cherry picking / accepting a patch.