The first one Utility is a series 70 most likely early 70's.The one you call the yellow Victa is actually a Vortex they are becoming quite collectible,you'd just need to fix the body and find a better cowl and you've got a very good score there.The other (sorry to say) isn't real exciting just a side start full crank engine.Certainly not worth much as a re-seller and not a collectible.I usually don't touch them as nobody wants them.The other two though I feel you've done real well.If you post the engine number (Of the Utility) up I'll be able to tell you what model and year model it is.
All in all good work and certainly at very good prices.

Here for a good time,not a long time.