Do I have enough hiding places in my tank for guppy fry?

I have read a lot that breeding boxes commonly cause stress to the pregnant guppy and apparently causes her to abort them or die or loads of other stuff I don't want to happen, so, since I have 6 female guppies all very pregnant I'm going to leave it and let the fry find places to hide...

It's a 165 litre tank with a large hollow boat, three little close together bushes, a sponge bob's pineapple house, two fairly tall plants (about three quarters of the way up the tank) and behind the boat there are two medium pot plants close together, the boat is almost at the back, so the pot plants are right at the very end of the tank providing quite a good place to hide (bigger fish don't have access to it)

If I don't have enough hiding places can anyone give me any idea's on something to make? What materials would be toxic or hazardous?

I have I few other fish too,

3 male guppies

10 neon tetra's

3 red neon tetra's

a leopard danio

2 black widow fish

4 white tetra

and 5 penguin fish

Will these fish be a problem?