May I cut down a grape tree for the need of expanding my backyard office?

Only through a gentile, and even then he should replant it elsewhere, except in Eretz Yisrael during Shemita in which case it should be removed with much earth and simply placed in a pot. See here regarding uprooting a fruit tree: https://shulchanaruchharav.com/halacha/destroying-a-fruit-tree/ See here regaridng shemita: https://shulchanaruchharav.com/halacha/from-the-ravs-desk-in-eretz-yisrael-may-one-uproot-a-tree-during-shemita/

If there is no Minyan in Shul, may and must the congregation remove the Sefer Torah and read from it without the blessings

They may if they wish, however, they are not required to do so. Whatever the case, each individual should read the Parsha to himself. see here: https://shulchanaruchharav.com/halacha/chapter-1-the-mitzvah-of-kerias-hatorah-its-general-laws/