I have the hexagon shaped picnic table for outside and really like it. Was surprised that it is still stable even if kids are only on one side - toddlers of course. Use it only for their outside drinks.

Inside I have an actual daycare table with adjustable legs that is called flower or cloverleaf or something like that. Basically it has 6 indent places leaving lots of room between the kids and when they are pushed up for meals the table surrounds them a bit similar to the highchair trays. Got it used off ebay for the cost of the picnic tables you are looking at you would be surprised how cheap actual child size tables are.

Also look at Canadian Tire. I have seen a childsize table with plastic top and it folds up just like the adult 6 foot tables do. I have seen people use the plastic lawnchairs for seating at the table.

Another option is to take an adult size table from a garage sale and cut the legs down to make it child height.

The problem I find with the picnic table is that the table part isn't very wide meaning each child doesn't really have enough room to put their stuff.