If you have a front-runner, tell it what you like most about it, what you need, want, don't need, and then tell it to give you 2-3 other options based on that info.
2.
Ask to pull themes of the pros and cons from user reviews on sites like Capterra and G2 and ask it to compare 2-3 products on your short list against each other thematically.
3.
Based on that, ask it what questions you should ask the SDR/BD given your business size and needs.
4.
Personally, I'd lean into the disco questions and see if the SDR is helpful. Some really will want to qualify you and if you're not a fit, won't want to send you through. Either way you'll be coming well prepared with lots of questions.