VHT = Very High Throughput = 802.11ac
HT = High Throughput = 802.11n
The first three sections are about optional features of the IEEE 802.11n and 802.11ac standards. They should all help and should not hurt, and you want them enabled unless you suspect that your client or AP has a buggy implementation of that feature that is causing problems.
LDPC is Low-Density Parity Check. It's a standard part of 802.11n and 802.11ac. It allows your 802.11 transmissions to be more efficient. You want it on for both VHT and HT.
STBC is Space-Time Block Coding. It's a standard part of 802.11n and 802.11ac. It allows your 802.11 transmissions to be more reliable and efficient. You want it on for both VHT and HT.
BeamCap/BEAM is almost certainly beamforming. Beamforming is a standard part of 802.11n and 802.11ac. It allows you to get greater better signal strength, and thus better throughput, at range. You want it on for both VHT and HT.
"Adaptivity" seems to relate to ETSI's (European Technology Standards Institute's) adaptive frequency hopping requirements which are mostly for Bluetooth. I note that ALFA says your adapter contains some kind of anti-Bluetooth-interference device, which is probably what this is all about. It probably has a stripped-down Bluetooth radio that simply tells other Bluetooth radios to stop using the frequencies that its Wi-Fi radio is using.
The Adaptivity settings you're seeing don't seem to have any direct correlation to parts of the ETSI adaptivity test, so it's hard for me to say what it's all about. Maybe someone with deep knowledge of how Bluetooth AFH works might know what these settings mean. Then again, maybe these settings are very specific to Realtek's or ALFA's implementation, so perhaps no one outside of Realtek or ALFA would know what they mean, since there doesn't seem to be any public documentation about them.