Jianshe flywing py80 engine question

[Camp345]

Hey y'all, I've some questions about my daughter's Jianshe flywing py80 (upped to 110cc top end). She been riding with the auto/4-speed transmission for some years now and ready for a manual.
She's been beating the bike up pretty bad over the years and has bent the shifter/shaft twice, as well as just put lots of hours on it. We just popped on a big bore and head last month, and she's loving the power. We slid the old stuff on a Pagsta bottom case we had sitting around, which look like they fit.
I think the pagsta was originally a 49cc or 97cc, so am I wrong, or can I stick the new 110 jug/piston/head on the Pagsta bottom end and move her into a manual transmission 4-speed?
The Pagsta has an electric starter so I assume I'll have to figure out how to wire the new engine as hers did not have any starter/lights/battery. Is this going to be a overly difficult task?
The Pagsta in question needs a side cover,dip stick, and possibly something else, but otherwise looks in decent shape. What do y'all think about this conversion?