Question about mixing soil with mulch and Spiders

I have a couple questions, can I mix Foxfarm ocean turf with regular mulch I got for free? the mulch is in pretty good condition. I'm just not sure about mixing the 2. Also I'm going to be planting next to a lot of dead leaves and spider webs, Should I clean the place up or should I leave the spider webs there? What kind of problems should I expect if I do the latter?

i dont know much about spiders hurting or eating your plant....if anything i wouldnt move or touch them cuz they'll be catching anybugs around your area which kinda like a pesticide....thats just my two cents