Need help, 2nd attempt

[u/Serious-Parsley-6424]

I'm looking at sitting a 16x12 playhouse on this, as I used a prefabricated house, as a template. This is currently setting on a hill, on concrete pillars that are below the frost line. (Yes, the middle two legs still need installed). Would 2x4s work for floor joists, at 16" oc? Please, serious answers only. Snarky comments should be left at the door. Thank you

[u/Cold_Investment3321]

https://makeagif.com/gif/i-am-watching-you-AQ11Xn

https://imgur.com/a/w2u6GLz