Mirabilis jalapa/four o'clock

Thank you so much! Yes, this is the plant :) I've just done a quick search on its proper care and so glad to now finally know that it thrives better if kept on the drier side. I've been worried since the last few weeks, it's showing signs of overwatering and dropping leaves. Now I know to leave it alone for quite some time. Thank you again!

The one at the left end looks like Portulacaria afra AKA baby Jade or elephant bush. ("Regular" Jade is Crassula ovata.) At the right looks like a Crossandra.

Without seeing the full cactus and flowers it's hard to tell, but my guess is Epiphyllum oxypetalum aka Queen of the Night. I find Epiphyllums one of the easiest to propagate. Just bury in some mix and leave be. Keep warm and in bright filtered light. No need to water till roots form. If you have a bathroom with a window. I would keep this in there. The humidity may help to kick start with the roots. The bathroom should have a window so there's airflow and light. These guys can get fungus. Normally for other cactus I wouldn't suggest this, but these are different.I've found roots usually pop out fast within a couple weeks. If they take longer it's fine;). You can water when roots form. No harsh sun for these guys. Like I said just nice bright filtered light. Remember these are rainforest cactus. Make sure to keep the mix fast draining so no soggy soil. My Epi mix is about 30% pumice, 20% perlite, and the rest cactus mix. Maybe your friend can let you borrow some of their mix. What hardiness zone are you in:)? Really helps when giving advice.