You need to know this, a Mormon on a mission is not in a rational frame of mind, and they are living a cult existence.
They have been primed for this for years, by family, church and friends, they actually believe they are doing gods work and have paid A LOT of money to be there.
They are living in a regime were they are never allowed to be alone, compulsory prayer and study of the Book of Mormon for up to six hours a day.
Enforced sleeping times, waking times and constant observation and observing for signs of "sin" in yourself and others. Food is limited and the best way to get a good meal is to find "investigators" and have them invite you to eat.
You are cut off from home and family, you may call home on Christmas day and on mothers day and that is it, you may not even go home for family funerals.
In may cases your passport will be taken away for "safe keeping" and will not be returned to you even if you ask for it as you "will not need it" until your mission is over.
Being sent home from a mission is a life long disgrace and stigma, comparable to a dishonourable discharge, and asking to go home early is like going AWOL.
You are subject to regular meetings and interrogations as to progress, made to feel a failure even if you are doing better than anyone else in the mission.
Questioned about your personal habits, including masturbation and those of your companion, they will go so far as to examine your bed sheets for signs of playing with your "little factory" a term coined by new deceased perverts in chief Elder Boyd K Packer and Mark E. Peterson (who actually recommended tying your own hand to the bedpost to avoid temptation), or worse for signs of "Same Sex Attraction" Mormons do not believe there is any such thing as homosexuality just the life style choice of SSA see the words of bigot in chief Elder David A. Bednar.

So no you are not going to get through to these kids while they are doing this, but as you say sow a seed or two that none LDS are not all drunken, debauched damned souls, because the two highest male demographics for leaving the church are returned missionaries who once recovered realise who awful their mission actually was and surprisingly former Mormon Bishops.

I watched psb doc on them and it dealt with Smith, his sexual wrongs, the racism. and polygamy but also what they did after Katrina. The N O police chief said " If there was a multi-national corporation who dealt with disasters. Then they would be the Mormons. They had trucks on their way to N O before the hurricane hit. They had a warehouse outside the city with tents, water, canned food blankets you name it and all of it itemised. ". Then there was an interview with one of the hurricane victims. He said " These guys showed up with orange jackets on. They helped out with food and water but then they also stayed and helped me clean up and fix things ". Just because theyre religious dont dismiss them.

I feel left out! I have never had a visit from a mormon of JW

All depends, do you want Mormon friends? Nothing wrong with that, but that's what it will come down to IF they stick around, which is unlikely if you try to de-Mormonize them.

Hey, ONCE you invite Mormons into your life they are akin to getting Bed-Bugs mate. Almost impossible to get rid of and nearly as impossible to reason with.
Trust me, been there done that.
NEVER ever invite them for a meal, they take it as a PERMANENT invite and will show up at their pleasure NOT yours.

Ignore them. They’re lost souls.

I think you have the exact right idea. Invite them over. Give them some down-time from their mission. They will be more willing to hear your side of the story. That's what I do.