start by differentiating your terms ..

potting media... is media engineered to move water thru a pot .. retaining what moisture the plant needs .. it can be varied according to the plants grown ... frankly.. its rather expensive to be spreading it in the garden ... but if you have the checkbook for such.. go for it ...

mother earth is soil ... it does not belong in pots.. mostly because it usually causes more watering problems ...

and .... finally.. dirt is what is all over you and the house.. after you play in either of the above ... the word mean nothing in the garden ...

i dont understand what you mean by adding soil at planting ... what do you mean ... little mounds??? ...

just put down the your mulch ... if later you decide to get some soil .. you can rake the mulch back and spread it around...

or get some compost .. and build your soil over the years ...

and then put the mulch back ...

and if you have reseeding plants already growing.. then just forget about it.. apparently they like what they have.. so why change it... this year anyway ...

ken