First time gardeners. Big plans, little knowledge. How can I deal with this?

We have recently bought our first house at the end of last year. The garden had not been touched in at least 6 years so after clearing out all the overgrown weeds, we’re excited to make it a place for wildlife.

We have a dirty bog-like pond with frogs, which we intend to upgrade and surround with wild flowers, fox gloves etc. Will I need to coax the frogs into the new pond? We also want to remove the fence at the back and place an evergreen shrub under that hedge. As well as making the middle section a lawn.

Our big looming problem is this big blooming hedge. Apart from blocking sun, it drops an obscene amount of dead leaves in winter which get stuck in our garden. I’m worried they will ruin pond life and other plants as decaying matter can be toxic?

I had a go at cutting some branches off in February and it has left a bald patch as you can see in the photo. If I were to trim it in November instead, would it regrow or would I get an ugly twiggy mess on our side? (The other side gets much more sun all day).

What evergreen shrub would you place under the hedge? Any other advice or ideas on how you would deal with this garden would be welcome.

TL;DR – Will trimming the hedge in December allow the leave to grow again or will it look dead? – What evergreen shrub would survive underneath it in place of the fence? – Will the frogs willingly move a the new & improved pond?