When is it appropriate to contact the editor before submission to avoid rejection without review? Manuscripts submitted to a journal are often directly rejected by the editor without going out for review. I find this acceptable with the caveat that it's a huge waste of time having to reformat and readjust word length. Journals with high rejection rates should have an abstract only submission as a first step.

Anyhow, given this current situation: should I contact the editor of one or more journals that I think would be a good target for my manuscript before formally submitting my manuscript?

Some journals offer this option but others don't. So I am not sure if it is acceptable to or if just by sending an abstract I will somehow limit my chances of getting to the review stage.
Thanks for clarifying.  Don't worry about the effect this would have on your future chances with this paper and this journal.  If this pre-submission step fails, that is an indication that the classic approach would also fail.  Either they feel it's worth sending out for review or they don't.

But send the whole thing, not just the abstract.  They need to be able to see the tables and figures.

When you send the full long version to the editor, here's a way to word the question: ask whether the work is appropriate for the journal.

If you get an encouraging response, then you can start slashing, do a formal submission, and hope for the best!

(Source: I have to give the credit to my spouse for this answer, who has about 250 publications.  Edit: in case this helps -- in the field of experimental physics.)