Yes, if they aren't Type 1 fonts then I don't think they pose any problems. I still don't know what an "x" font type is, though. Seems it's just a system designation of some sort, but these are actually TTFs. You can always hide the fonts you don't want to use, so they don't show up in your font list within your applications. But they are still there on your system if you ever have an old document that calls for them, so you can investigate further.
(Just to add that I find this reference information helpful, too, when I go looking for fonts.)
Fonts types that can be embedded within documents: All TrueType and OpenType fonts have “embedding permissions” encoded within them, these are typically set by the font’s supplier, and are defined as part of the OpenType font file specification. There are a number of settings, but the main ones of interest are as follows:
- No embedding—The font supplier does not allow embedding. These fonts are quite rare.
- Print and preview—The font supplier allows for embedding but the document is locked and cannot be edited. Most third-party fonts have this setting.
- Editable—The font supplier allows the font to be embedded within a document and allows the document to be edited using that embedded font.
- Installable—This is the most permissive setting. The font supplier allows the font to be embedded within a document, and permits the document viewing application to permanently install the font on the user’s computer. Most applications treat these fonts like those set to Editable embedding.