So, i watch the entire video and, even if i make EDM and not Lo Fi Hip-Hop (this was new for me, it's an interesting genre), i think i can help you.
For
Drums you can download samples for example from here
-
www.youtube.com/watch?v=5ek0o9DtSps
-
http://samplegang.com/2017/12/10/vol4-f ... y-badmath/
-
https://soundpacks.com/free-sound-packs ... -drum-kit/
You can find Reverb and Delay in LMMS itself (i personally use C Plate for Reverb and Canyon delay) or you can download some VST effects like these.
Reverb:
-
http://vst4free.com/free_vst.php?plugin ... rb&id=2870
-
http://vst4free.com/free_vst.php?plugin=Ambience&id=568
Delay:
-
http://vst4free.com/free_vst.php?plugin ... ay&id=2426
There's also a new one that is Speculum Free but it doesn't work in LMMS
For that
chill vibes/keys sound you can try
Synth1 that covers all kind of music. Just search for the right preset or create yourself the sound you want. You can try also
Alan Vista's VibroMaster with some effects and
Dead Duck's DDX10. Take a look at
Gluereeds for a great EPiano.
Tyrell Nexus 6 is a great VST, too.
The
Omnisphere sound looks like a piano with lowpass filter, reverb and delay. If you have a good computer try out
Samplescience Player, is best free rompler like Nexus, Lethal and Omnisphere.
I don't use
Arpeggiators but you can try
Kirnu, it seems the best freebie at the moment.
For that
guitar sound i don't know but i think you can find a similar one in Synth1 again.
For the
lead sound try LB302 with some FX.
For the
organ sound it seem a hammond, try out
NubiPlus by fxpointaudio.
For the
flute LB302 or ZynAddSubFX could help you.
Finally i have to say that i think that Synth1 have all the sound cited above and in the video.
I hope this helped you.