The evolution of P/F vs T/K raises important questions

[cvetkakocj@rogers.com]

These similarities are purely external and not always clear-cut. a is clearly similar to a, but ch can resemble ce, ct, ee, cc, and even tt. s is similar to some forms of writing the letters e and t in abbreviated words.
d — it’s unclear what it is. It could be either d or s. l looks like both e and x, but the angle doesn’t match (neither the curl of e nor x points upward).

And so on...

In addition, we know that the VMS alphabet is constructed by adding various strokes to two basic forms. This is clearly visible in r-s, b-n, g-m, y/l. That is, even if there are similarities, in the context of this system they are purely coincidental.

It is true that ch can be read as ce, cc, ct, ee, but that is not the problem of letterforms, but of transliteration. Most of medieval handwriting is very ambiguous and unless you know the language, you cannot read it. So, you cannot build transcription alphabet on ambiguous letter combinations.  As for EVA r and d - they were used in the same letterform in many 15th century manuscripts for r and d respectively, often alternatively with the other shape. EVA s and b look like mirror image of Latin S and b. In EVA transliteration, b is greatly underrepresented, because when it is written as a mirror image, the bh, be, bc looks like EVA sh.
In German writing, the c/z shape was changed to z with the tail, so that ch became cz. 
Different nations use different Latin combinations for ch/č, like ch, zh, cz.