Change Data Capture For Java Processes And Not Databases?

oracle 11.2.0.3 I have insert only tables that receive srecords from multiple processes at a rate of about 200/second. Each transaction can have up to 100 records. I have another set of processes that queries this table for the latest data. These processes run anywhere from once a minute to once an hour. Processes do not get all of the data. They get data based on a type field.

Both of these are from java middle tiers. The process that queries data (The subscriber) does so at the request of many remote servers (there will be vast numbers). I am not allowed to expose these downstream databases to the internet (they are not oracle DBs anyway) so I cannot use streams or golden gate

So basicallyInsert Process: multiple sessions that combined insert records up to 200/second. There will be between 1-100 records per commit.

Query Process: Downtream process makes a request to my middle tier. This middle tier runs a query to get the latest data and passes it back. This design is set and I cannot change it.

1. right now we capture the insert time of the record. However, at this rate of inserts some processes will commit faster than others. So I cant use a 'greater than my insert time' query.
2. streams/golden gate won't work. can't register these DBs.
3. don't want to serialize my inserts because since I am not sure I can keep up with the insert rate. I don't even know what the specs will be for the production hardware. I have to actually deliver this before its decided. So I am being conservative.
4. I really want to avoid updates on this table if possible. In part due to my limited ability to test.
5. due to the number of downstream processes it is possible that it will request data and for some reason fail to insert the data locally. So the downstream application will keep track of the latest data it received. This means that a subscriber may need to request the same data again.

Is there a way to set up change data capture with multiple subscribers to handle this? if my subscribers are just queries? All the queries come from the same servers(there will be several, but all the same thing). If so, when I performance test this are there any wait issues I should keep an eye on?