I guess I am really confused ...
I thought you were adamantly against building a c&c cage because you didn't feel it was safe enough for your pigs with the other animals in your house?? ...that is why you insisted on a wood structure.
If you have other pets that make you concerned for your pigs in a c&c cage, a mesh dog playpen is not suitable at all. It can be collapsed by a pet jumping on it or simply pawing at it.
You should prepare them with safe housing that can be cleaned properly. A mesh enclosure I guess could be ok for a day or two under close supervision, but I would not leave them in there for longer than that.
I am sorry but I certainly don't think it's appropriate to take on more when you are not properly prepared for the 2 you just got.