different versions of the same letter

Fonts and More Type Design
2

Your previous question was answered, but you never followed up.

  1. Can be done as explained there. You just need to set the side-bearings correctly but swashes may collide with other glyphs requiring the use of contextual alternates.

  2. You can do with Contextual Alternates or Character Variants.

OpenType features are not supported by all applications, but support is gradually improving. Serif applications have supported them for many years, and LibreOffice also does now with some code that is not very user friendly. Recent versions of Microsoft Word also support them, but I am unsure which features it supports.

Give the alternative glyphs meaningful names such as t.alt0, t.alt1, etc., and add a contextual alternates feature using FontCreator’s OpenType Designer.