Not sure I understand the problem.
Mobile friendly or not shouldn't effect search visibility (other than possibly ranking lower - but not sure whether that is something eBay does).
I looked at your item 192841296384 using Firefox 31 browser on desktop from the US. Looks fine.
I searched with a partial title REAL ANTLER WHITETAIL DEER OVAL using Opera Mini browser on my phone and two of your listings came up just fine plus a carbon copy sponsored version of the 192841296384 item result. Not seeing the problem.
Your friends in Canada, Philippines, and Georgia shouldn't be able to find any of your listings at all using any device, desktop or mobile, because if the item doesn't ship internationally.
When I change my location to Georgia (the country) on the desktop all your items disappear from search. They should from your store also, but it looks like ebay has messed with the store stuff again, and when I re-load your store homepage it pops up a "where are you" dialog that then redirects to a new store search and fails in a empty broken page. (in FF31 or FF52 and looks like may be another issue with broken search)
Viewers in locations you don't ship to won't find you in search or and shouldn't see those items in your store. They would be able to see items when directly referenced (ie:
https://www.ebay.com/itm/192841296384)
Item 192841296384 does not ship anywhere other than the US, so your friends shouldn't be able to find it. Some (or all?) of your other items do ship internationally, and they should appear for your friends in other countries, but should also appear for me in search when my location is set to Georgia and they do not.
I also checked item 192841296379 and item 113659160764 - neither one ships anywhere but the US and won't be visible in search to anyone not in the US.
We need to narrow the problem down.
None of those 3 items should be visible in search to your friends in other countries on any device - desktop or mobile. Some of your other items do appear to ship internationally and should show up for them desktop or mobile. (pretty much I'm saying that your info about what they reported is incomplete and is confusing the issue at the moment)
Are you saying that YOU (in the USA) can find those three items in search using a desktop or the mobile app, but NOT a mobile browser?