Well I hope I'm not too late in saying this, but ppg recommends that base coat should be applied over DP within 7 days of being sprayed. Meaning, after you spray DP, you have a 7 day window to apply base. If you are passed your 7 day window, it's recommended that you apply another coat of dp before paint. Not sure if you knew this but dp is also a sealer. When mixed 2:1 (dp:402 or 401) it's a primer sealer, when mixed 4:2:1 (dp:402 or 401: reducer) it's considered a sealer. The reducer helps with flow and it lays on very smooth.
So I would suggest before you spray base, spray one more coat of reduced dp. You shouldn't have to sand it if applied properly and it'll cover those small bare metal spots you mentioned.
Also ppg says you only have 24 hours after applying basecoat to apply clearcoat, assuming you're using the deltron line.
Could you get by without another coat of dp, yea probably. But if I were you i wouldn't chance it.