boy, you've set some tough parameters. For the single point tools and boring bars, a small manual surface grinder is the ticket if you can't bear to freehand. You can use a vise,a sine plate, or various cheap spin indexes (I mean the really cheap imports, not a suburban) to hold the work.
For instance, I have a 3/4" round bar with a 1/4" keyway milled in the end. I mount this in a collet in a cheap index, put the lathe tool in holding it to the bar with a small lathe dog. Then I dress the surface grinder wheel, and can use this to very closely get ideal threading tools with optimum leading and trailing relief for the thread pitch at hand. I started using it to make square thread and buttress thread tools, which have very little leeway and for which there are no fishtail gages made. Now, since I can hardly see small stuff, I use it for other thread tools too, including common 60º.
As mentioned in a previous post, I grind all other lathe tools freehand by eye. But you can easily do them on the surface grinder if you want to spend all the extra time.
For drill points, you can use a cheapo sharpener like those made to sharpen bits to a bench grinder; on the surface grinder. Or you can get a Polychoke or similar index which is offset in the main bore to provide variable radial relief as the bit is turned. With a little thought, you can use these to do accurate web thinning, or true split points. (theres a number of manufacturers of different styles) Whether you want to or not, these are also good for taps, and i have used one to make special thread taps.
Your complication is the broach requirement. If they are all really short, you can do them on a surface grinder. But the wheel points the wrong way for practical use. You can watch ebay for a right angle head for the surface grinder, and then do broaches up to the x axis capacity. But generally speaking there is no x axis micrometer dial or index. A flicker finger can be used to indicate off the previous tooth; this does presume broaches with uniform tooth spacing.
At this point, a tool & cutter grinder starts to look more practical because it is easier to orient the wheel cross ways to the longest axis. But again, the longest axis most likely does not have a mic dial. One procedure is to clamp the broach to the table with the teeth overhanging the edge. This is an option if the wheel head on the particular T & C grinder will lower (or table rise) so the wheelhead is centered on the edge. cuts. But any other than a very narrow broach requires motion on all 3 axis to sharpen each tooth! (table x to index, tabel in to plunge, wheelhead rise and fall to traverse tooth).
Either machine will do single point tools, almost a no-brainer. The t&c with a tilting work head or vise is a little more versitle, but the surface grinder with mag chuck may be more convenient once you work out a procedure.
Either machine will do drill points conveniently..... with an accessory for radial relief.
T&C manuals sometimes show broach sharpening but the one I've seen that specifically reccomends it, including photos, (Le Blond of Cincinnati) is vague to the point of obscurity about tooth indexing.
If broach sharpening is important to you and you don't want to get a real broach sharpener, maybe consider getting an auxilliary spindle (often called high speed spindles, but heavier duty ones can be had for say 3600 rpm too) and mount it to over hang the table, wheel crossways, when you want to do broaches. Then you can set up to index with the table and traverse to grind with the table in-out.
Personally, I think a 6 - 18 size surface grinder, add the attachments you need, would be good for your needs. Added benefit is the addition of a surface grinder, too, for other uses and tools. It could take a while to catch a right angle head, but they are out there, or you could make one.
smt
