With the other structure you have around the tubes in that underside, I wouldn't worry about strength. If you're landing THAT hard on the belly it's gonna hurt something else as well ...
Accessing EDFs ... Maintenance? ... Did I spell that right? ... LOL - Basically never. I fly pretty gingerly for the first few flights to enjoy whatever I just built, but not long after I get it dialed in I start to fly pretty hard to see where the limits are, and the EDF is never the limiting factor...UNLESS I've mis-sized something electronically and fry the motor, which I've only done once on my small Goblin-Jet. I basically ALWAYS wear out the airframe before wearing out the EDFs.
Good to know, I am beginning to suspect the first EDF fans I got were really sub par. I had several break for no apparent reason and some break with hard landing(noob pilot). The ones you sent me links to are built like a tank by comparison. If they hold up like you are describing, I will be a happy camper.