Hello Bee,
As for internationalization purposes, leave them in their own ccTLD. Just add hreflangs to the other country websites and you'll be just fine.
If you choose to go down the road of having all under a .com/country/ configuration, I'd suggest you installing separate wordpress on each country. Also, if you plan on expanding on more countries and having an overall control, take a look at Wordpress Multisite Network Administration.
Also, just for clarifying, take a look at these articles:
Multi-regional and multilingual sites - Google Search Console
International checklist - Moz Blog
Using the correct hreglang tag - Moz Blog
Guide to international website expansion - Moz Blog
Tool for checking hreflang anotations - Moz Blog
Hope it helps.
Best Luck.
GR.