Hello u/sounds_abt_right

You want some kind of echo/reverb for your voice for a decent experience.

If you want to stick with the Innopow (which are great) and your Lynx I would add this mixer

https://smile.amazon.com/Pyle-Compatible-Professional-Interface-Mixing-PMXU48BT-5/dp/B07Y8M52HN?th=1

I agree with u/Full_Apple_1224 with their recommendation of a different version of the LyxPro 8” which has echo.

Their recommendation of the LyxPro SPA-5.5 also might be a good option for you.

Yes, you need a mixer. Something like this

https://www.amazon.com/Yamaha-MG06X-6-Input-Compact-Effects/dp/B00I2J4V5G

You would plug the audio output of the laptop and the mic into the mixer and the plug the output into the Rockville speakers.

If you want to go super cheap I have this one and it works well enough.

https://www.amazon.com/Pyle-Compatible-Professional-Interface-Mixing-PMXU48BT-5/dp/B07Y8M52HN