"do you think the homewrap version is breatheable enough for a small single wall tent ?"
Certainly if you have enough venting. Awhile back, i made a modified tube tent out of homewrap, and it worked fairly well except when it was very humid. But there wasn't enough venting. Keep in mind though, homewrap packs rather bulky, and a tent is going to be especially big and bulky. A mid sized tarp would be better.
"is the clothes version strong enough for a single wall tent ?"
In my opinion no, which is unfortunate because i really like the "Kite" (or "clothes") tyvek material for it's breathability, smaller packing, less slippery, and lower weight over the homewrap. I made a double bivy out of it, and my wife didn't take any care and would sit up abruptly not paying attention to straining the material, and after only a couple of times it has started to rip and fray (i've since converted into two single bivies). Homewrap is much tougher and strong.
Plus the lighter, more breathable stuff, it's not near water resistant enough to use in a tent unless you plan to never take it out in rain. (Home wrap is though)