Three questions on edge joining a table top

Here's my take…

Q1 : How wide/long are these boards, and where along the length is the gap located? If its an 8' board, and the 1/32 gap is in the middle, depending on the width of your boards, it might now be an issue. If it's a 4' board, or the gap is on an end, it might be an issue.

Q2 : I'd skip the biscuits. I've done larger (around 6-7') panel glue ups with and without them, and I prefer without. Instead, I'd recommend using some cauls (I made mine from scrap 2-by douglas fir). I find I get better results, as the biscuits still have some play to them. Also, the cauls raise the workpiece off the bench and make it easier to alternate clamps above/below. Just be sure to either wax your cauls, or put some cling-wrap on them so they don't end up glued to your table top.
Also, if you have a lot of boards in this glue up, it may be easier to glue them up in pairs, and then glue those together. Sure beats trying to spread glue on a dozen boards and then get them all aligned and clamped. And, if you have a planer, you can plane the sub-assemblies flush prior to the final glue-up, making the final flattening a bit easier.
Yes to leaving it long. You want to clean the ends up after.

Q3 : Last top I built, I left it about 6-8" longer than finished length, and then cut to length with a circular saw and an edge guide. Worked out real well. I had a simple guide that, when clamped to the work piece, had zero clearance on the guide-side, so tearout was a non-issue. I also put a slight chamfer on the edges.

Great responses, thank you.

The boards are 22" long, final size is 18". I have an edge guide and am pretty good with the circular saw, so that's a welcome approach. I was a little concerned about wrestling with a large panel (this is not one, but as a general rule) anyway, so I'm glad there's a "bring the tool to the work" approach.

I did make some cauls. In fact, I was trying to put a slight convexity to the edge with the hand plane, but failed at that. I do have them covered with duct tape for glue avoidance.

The boards are about 7" wide, so a subassembly will be too large for my 13" planer. They are pretty flat all the same so I think my ROS will get them flat when the time comes.

Thanks for the "no biscuits" consensus and also for the guidance about working in subassemblies. I only have three boards per top (2 tops and 2 shelves here), but going slow on the glue up is a good idea especially for a first-timer.

What mistakes are you seeing in your hand planing? It took me a while to be able to get somewhat decent results, but there are plenty of good videos out there.

You understood correctly, you take two adjacent boards, and fold them shut like a book. Then, you put them in the vise and plane the edges together. When you the edges are flush, and you can take a full pass shaving, take them out and unfold them. They should match up perfectly. For me, this usually takes 2 or 3 tries, but I get it. The nice thing about this, is if you aren't planning at exactly 90 degrees to the side, as long as those edges end up flush with each other, and small amount off on the angle should cancel out when you unfold them. I've seen this done on Rough Cut, so you could try looking up Tommy Macs video. I'm sure countless other people have posted videos, that's just the one that comes to mind. It's made my panel glue-ups much less of a headache.