I can't foresee a major problem, some of mine are stacked in a similar way.
You've not made a common mistake of putting the wider one on the bottom that most people make, if you had done that then you'd find the doors on the wider one probably wouldn't have opened.
Yeah I worked out that would be a problem before i did it. You can also just see in the pic I have put some thicker wood in between the two to stop the top one from bowing.
1.1.0 Amel Corns Colin and Xena 1.0.0 Dog Talan 1.1.0 Cats Wotsit and Willow 1.0.0 Ferret Chaos
2.5 corns 2.0 cali kings 1.0 tange hondo milk 1.0 apricot pueblan milk 1.0 royal (overgrown slug) 0.1 tarantula 1.0 chinchilla chico, 0.1 goldfish tigger 0.0.4 minows 0.2 cats fudge and porsha and 0.3.2 tarantula’s that are my mummys r.i.p to the lil ones that i and mummy have lost recently