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Spectroscopic data are necessary to break degeneracies in asteroseismic modelling of the interior structure in high- and intermediate-mass stars. We derive precise photospheric stellar parameters for a sample of 166 B-type stars with TESS light curves, suitable for detailed asteroseismic studies, through a homogeneous spectroscopic analysis. The variability types of these stars are classified based on all currently available TESS sectors. We obtained high-resolution spectra for all 166 targets with the FEROS spectrograph in the context of a large program. The Least-Squares Deconvolution method is employed to investigate spectral line profile variability and to detect binary systems. We identify 26 spectroscopic double-lined binaries; the remainder of the sample are 42 supergiants in the LMC galaxy and 98 Galactic stars. The spectra of the Galactic stars are analysed with the zeta-Payne, a machine learning-based spectrum analysis algorithm. We determine the five main surface parameters with average formal precisions of 70 K (Teff), 0.03 dex (logg), 0.07 dex ([M/H]), 8 km/s (vsini), and 0.7 km/s (vmicro). The average internal uncertainties we find for FEROS spectra with our spectrum analysis method are 430 K (Teff), 0.12 dex (logg), 0.13 dex ([M/H]), 12 km/s (vsini), and 2 km/s (vmicro). We find spectroscopic evidence that eight of the 98 Galactic targets are fast rotating g-mode pulsators occurring in between the slowly pulsating B (SPB) stars and delta Scuti instability strips. The g-mode frequencies of these pulsators are shifted to relatively high frequency values due to their rotation. Their apparently too low Teff relative to the SPB instability region can in most cases be explained by the gravity darkening effect. We also discover 13 new HgMn stars of which only one is found in a spectroscopic binary, resulting in a biased and therefore unreliable low binary rate of only 8%., Comment: 17 pages, 13 figures, tables A.1 and A.2 will only be available in electronic form at the CDS. Accepted for publication in Astronomy and Astrophysics

The most powerful tests of stellar models come from the brightest stars in the sky, for which complementary techniques, such as astrometry, asteroseismology, spectroscopy, and interferometry can be combined. The K2 Mission is providing a unique opportunity to obtain high-precision photometric time series for bright stars along the ecliptic. However, bright targets require a large number of pixels to capture the entirety of the stellar flux, and bandwidth restrictions limit the number and brightness of stars that can be observed. To overcome this, we have developed a new photometric technique, that we call halo photometry, to observe very bright stars using a limited number of pixels. Halo photometry is simple, fast and does not require extensive pixel allocation, and will allow us to use K2 and other photometric missions, such as TESS, to observe very bright stars for asteroseismology and to search for transiting exoplanets. We apply this method to the seven brightest stars in the Pleiades open cluster. Each star exhibits variability; six of the stars show what are most-likely slowly pulsating B-star (SPB) pulsations, with amplitudes ranging from 20 to 2000 ppm. For the star Maia, we demonstrate the utility of combining K2 photometry with spectroscopy and interferometry to show that it is not a 'Maia variable', and to establish that its variability is caused by rotational modulation of a large chemical spot on a 10 d time scale., Published in Monthly Notices of the Royal Astronomical Society. 20 pages, 10 figures and 10 tables