The OSC is determined by your choice of synth engine.
Every synth engine in the OP-1 has an ADSR envelope you can tweak. That is your AMP.
FILTER... well, most of the synth engines are not VA/subtractive synths. Did you know that the most famous FM synth in history (Yamaha DX7) had no resonant filter at all? The exceptions are DSynth/DBox. They do have FILTER. You could use Punch as a FILTER but it takes up the FX slot and you only get one FX per synth preset.
Yes, you get one LFO per synth preset. As in the case of the ADSR envelope, it doesn't matter which synth engine you choose - you get an LFO.
Looks like it's time for you to take a look at the online Guide - it explains the a lot about the synths, the LFO (types of LFO, how to assign destinations, etc.).
The section on the synth LFO is found here:
Some details on DBox/DSynth found here - looks like the filter cutoff frequency is adjustable but not filter Q.