We have an older man (Frum, unrelated) staying by us for a few days and my husband is leaving town for the weekend while I want to stay here with my two children (both under five). Is there any way this can be done without being a problem of Yichud?
The children don’t qualify as Shomrim.
There however are several potential solutions. See the references below for all the relevant details.
* If he brings another two kosher men with him for the night or one child 5-9 years old. By day, one other kosher man is sufficient.
For the definition of kosher men, see here:
For references, see #2712
* If you have CCTV.
* If you hand out keys to neighbors.