Humid set up for a BRB , advice please !

[Zincubus]

Hey *peeps , I need a little advise/input on a little project .

I have a young Brasilian Rainbow Boa coming in a few days time and I would like to have a real nice set up ready and waiting.

I have an Exo Terra viv , something like 2'6" long *x 2' x 2' , I'm pretty sure the bottom 3" section is watertight .

Considering that BRB's like pretty humid conditions I'm going to cover the mesh lid with something like perspex or something. I also intend to use *plantation soil *as substrate . I'm pretty confident of making a decent job of things set up wise but I was wondering about making use of the soil and putting some living plants in there.This is where I need some input/advice please. *I don't want anything toxic or poisonous or that's going to be an irritant obviously but I was thinking about some little wild flowers like daisies or clover or similar ??
*My son suggested planting some grass seeds but I fancy a bit of colour and texture .
What do you folks think ??

Are there any little compact plants thatI could buy from a garden centre maybe ??

Another idea but probably too ambitious for me would be to build a little water section in at one end of the viv , you know gently sloping into a *couple inches of water ??? *I'm thinking it's a step too far as I can't think how I'd keep the soil from slipping/sliding into the water .

Any suggestions or advice ?