I think that's a really well-drafted starting niche. You could definitely tell wholesalers, realtors, etc., that you're interested in all houses built in the 80s or later, worth 100k-120k after repairs with light repairs only, with no HOA and they'd know what to start sending your way. I would hold the rent numbers in your pocket, unless you specifically get a request from someone asking what rental rates you're looking for.
I think the other things that folks are mentioning here, is that your niche will change as you go. So maybe you print your current niche onto labels that you can add to pamphlets, so that as your portfolio grows, you can still use the same pamphlet (potentially), and just update the text on the labels that describe your niche. (I did this on the backside of my REI business cards. I have "Looking for..." as a heading, and then I hand write my criteria on the back. This has also allowed me to write in what I'm hoping the person can help me with. For example, on one, I wrote "a mentor". On someone else, I wrote "a JV partner". etc.)