So both tmave and svetle are "adverbs" and therefore don't need to be in agreement with the word they're modifying (i.e. "tmavou/svetlou cervenou hrusku".)? Now I have to reach back into my dim past and fetch up what exactly and "adverb" is. Hmmm... No rest for the weary.
It is common to connect prepositions with the subsequent word. In all languages I know.
You should not skip any letters except some specific cases (jsem -> sem, jsme -> sme). You may find it difficult to hear some consonants, but they have to be there and a native speaker would immediately find it missing or would not understand you.