Are non-first authors less likely to be invited for peer review? In fields where the order of authors matters (e.g., health and medical fields), does the order of authors of published papers generally affect how editors choose peer reviewers for new submissions?
Can someone who has never first-authored a paper, but is listed as a non-first author in many papers (with several other authors), be invited for peer review?
Is there any relevant published data?
Certainly someone with no first-author papers (or indeed no papers at all) can be asked to act as a reviewer. However, I think it is relatively unlikely, if only because it can be hard for the editor to be confident what expertise that person actually has (perhaps they're the statistics guru and don't know anything much about reaction pathways in biochemistry...). In contrast, it is a reasonable first assumption that the first author of a paper is broadly capable of reviewing similar papers.
Of course there are exceptions: the editor may know the individual personally; the individual may be recommended/suggested by someone else; they may have a strong reputation in their own right without ever authoring papers (e.g. if they are a specialist lab technician).