I don't find them in Unicode 6.2. I have never seen them or had a request for them. The fact that they are not needed probably has to do with the rules pertaining to Long S usage, but that's just a guess.

That doesn't prevent you from including them in your fonts if you want to do so.

No, they're not in Unicode as precomposed characters. There are a couple of ways you could handle this.

1. If you are relying on the long-s character to differentiate this form from the regular lowercase s, than these diacritics would be best encoded using the long-s character followed by an appropriate combining mark character from the 0300 range. These combinations could then be mapped to precomposed glyphs in the font using the {ccmp} layout feature; alternatively, you could rely on GPOS mark positioning.

2. You could instead handle the long-s as a glyph variant of the regular s, invoked by e.g. the {hist} feature or a stylistic set feature. In this case, you would handle precomposed long-s diacritics in the same way.

Note that a single font could support both approaches.

[George mentioned rules for long-s use. It's tempting to try to use contextual lookups in the {hist} feature to apply these rules, but be aware that the rules are not uniform across languages or, even, time periods.]

Thanks George and John! This is most helpful

http://typophile.com/node/103507

Also, your first five glyph names are not AGL (or AGLFN) compliant. Better glyph naming would depend on which method you wish to use to access the glyph:

e.g. /scaron.long vs /longs_uni030C

I have ſeen long s with dot above uſed at ſome point, but I don’t remember where. That’s the only diacritic I recall having ever ſeen used ſpecifically with long s.

If you’re ſeriouſly thinking about long s then you should read up on its uſage patterns ſo that you underſtand how it was uſed and in what contexts. Andrew Weſt’s BabelStone blog has two poſts on it: The Rules for Long S, and The Long and the Short of the Letter S. Note that the diſtribution of long s changes over time, and alſo that it’s different between languages in the same time periods.

I presume by longs_i and longs_l you are referring to ligatures with thoſe lowercase letters? Then you should alſo conſider doing a ligature with /t/ depending on the ſtyle, and poſsibly also with /b/, /k/, and /h/ depending on how ‘French’ you expect uſers to be ſetting their texts. A ligature with another long s is probably a good idea too, unleſs you are uſing a more ‘buttonhook’ ſtyle like in Linotype typefaces.

The italic /ſ_t ligature is really weird the way the ascender of the t is elongated.
I mean, there is no functional reason for this ligature (i.e. to avoid a collision).
IMO it’s made to echo the quaint /s_t roman ligature.