No do not keep them with anything else, they live perfectly happy with each other but even 1 lovebird with other species can cause a fair bit of damage without trying hard.
They breed happily in a large aviary without as many problems that the budgies do. Space, good size nestboxes (not too big, not too small) but enough room for them to have a clutch of chicks and also fill it with nesting material
When you are set-up, supply them with palm fronds (date/cotton are okay) long grasses etc anything they can shred up and weave into tunnels inside the nestbox I found this stimulates some breeding. Mine fill the nests with any vegetables, grasses, green pick that I give them to eat also so have to keep an eye on that sometimes
Once they start breeding you are right but same as other birds its getting them to feel right. Mine went near 4 yrs without then all of a sudden the population tripled. Ive mainly blue series masked, some green and others all masked. Im not big on the peachfaced but there are some nice ones around
I'lll try and find some pics for you