I've been reading this post very closely because I am in a similar situation - applied to both U.S. and European programs with the desire to experience an MBA education abroad (with potential to live abroad post-MBA).
But I also have the same concerns about COVID-19 for the international schools I've applied to, and it's making the choices extremely difficult.
Being from the U.S., I worry about what the job market looks like next summer for internships and visas, as well as the potential for travel to be inhibited (imagine being in London and being restricted at times from traveling to see the rest of Europe), let alone the impact to the actual in-person experience (move all the way to Europe to sit for periods of time in your flat doing virtual classes..). While these are more extreme scenarios, they aren't out of the question it seems.
If your goal is to live abroad post-MBA, then under normal circumstances LBS is the best choice. But these aren't normal circumstances, and the risk level seems to be higher now for European programs (if you're an international student). Deferring could be an option, but to wait another year is tough, and the situation might still be the same. I suppose it all comes down to your risk tolerance, at least in my current experience/decision process. Because of that, I'm leaning towards U.S. schools (also because there's a chance I work in the U.S. afterwards anyways), but thinking about other ways to get abroad down the road, as you are as well.
One thing that you do have in your favor for LBS is that the Tier 4 Student Visa you'll have can convert to a Tier 2 Work Visa if you get hired by a company in the UK before your official graduation date (i.e you secure a post-MBA job before graduation). My understanding is that you won't count against the "national limit" for foreign workers in that situation. This means you'd bypass many of the visa hurdles that you'd normally experience as an international student in a different country. So the economy might be doing poorly, but you'd still have a fighting chance to get hired, and wouldn't be inhibited by your visa status. That is, of course, if these rules still apply given the current situation.