Yes, you can reimburse your qualified medical expenses incurred in 2018 (if fact, any incurred after the establishment of HSA #1) from either of the HSA accounts without doing any rollovers or transfers. Since you had an nonzero HSA balance at some point in the 18-month period prior to opening HSA #2 (you apparently never had a nonzero balance in HSA #1), your HSA establishment date of HSA #1 carries over to HSA #2. See IRS Notice 2008-29 Q&A-41:
https://www.irs.gov/pub/irs-drop/n-08-59.pdf
