Ah, yes I did spend some time working with Lv2Host and reading a lot of the @lokki 's code on that thread. It seems that he parses the midi first before sending integer/float control data to the plugins, while I'm looking to connect the midi directly to an exposed midi port on the plugin for full control (i.e. the plugin parses the midi). For example the last two ports listed for the Calf monosynth plugin are
Port 52:
Type: http://lv2plug.in/ns/lv2core#ControlPort
http://lv2plug.in/ns/lv2core#InputPort
Symbol: o1_xpose
Name: Osc1 Transpose
Minimum: -24.000000
Maximum: 24.000000
Default: 0.000000
Properties: http://lv2plug.in/ns/lv2core#integer
http://lv2plug.in/ns/ext/port-props#hasStrictBounds
Port 53:
Type: http://lv2plug.in/ns/ext/atom#AtomPort
http://lv2plug.in/ns/lv2core#InputPort
Symbol: midi_in
Name: MIDI
Properties: http://lv2plug.in/ns/lv2core#connectionOptional
Port 52 is a regular integer control port, Port 53 is an AtomPort and I want to to send midi data directly into that I think. It seems like this type of port is not supported in the Lv2Host code, but somewhere in Jalv I think there is some support for this. So I got to the point of deciding if I should try to add midi port into Lv2Host, or switch to Jalv or try to hook things together without using the Lv2 interfaces.