98 in. Cutting Guide

Yes

The small piece is connect the two larger straight edge pieces there's two set screws with the set screws in the small piece in the holes pre-drilled slide the small piece onto one of the larger set the set screw slide the other piece onto the smaller piece and set the other set screw to make 8-ft cuts

Yes,it will flex at the junction. one can use double sided tape at the junction or clamp a piece of scrapwood at a right angle to the cut whereby the end of the scrap wood abuts the junction and the other end is clamped to the opposite side. carpet tape, given its low profile, would be ideal if one doesnt have suitable scrap material.

The tool is very simplistic smaller piece slides onto each of the larger pieces to make it into an extension the set screws go in the little holes on the small piece to hold it true work so much better than the $200 slide guides for the price

It's a very basic tool just like a level the smaller piece slides on top of each of the larger pieces to make it longer the screws are set screws to set it in place so nothing flexes or moves for the simplicity it works great

You received a plane straight edge there shouldn't be a handle on it anyway a handle would just get in the way of the saw just run your saw tight against the higher edge of the straight edge makes perfect cuts every time

If you set the guide wide enough so you can slide the blade guard or "foot" of the recip saw along the guide, yes. If you wanted to just ride the blade against the guard I don't think your guide would last very long as a recip saw can cut aluminum.

Mine did come with small c clamps

Can't be certain, might be a substitute product or all required peices were not shipped to you.

It will not flex if clamped properly