1) Can we have a date along with Timestamp which can be used as a criteria for query?
The date field in Funnelback ignores any timestamp information. There is an open ticket about extending support for this. If you require any timestamp information you'll need to use a different type of metadata field (either a numeric one carrying something like an epoch value, or use a text field).
2) Can the date with timestamp be used to sort the data.
If you use something like an epoch date or a date format that text sorts correctly (like YYYY-MM-DD HH:mm:ss) you should be able to sort the date fine. You just can't use the date field explicitly.
3) Where do we need to change the config to support date format with timestamp
As mentioned above there is no support in terms of date metadata for timestamp information. If you use an alternate metadata field for the date it's still a good idea to have the day level date mapped to metadata so you get date information into the ranking algorithm (dates mapped to other metadata fields are not treated as a date).
4) For query with events i am unable to get response using the following http://example.com/s/search.html?collection=events&query=eventType:anniversary % O>20190101<20190225. It gives 400 error, unable to parse URI query.
% is a special character in a URL and needs to be URL encoded.
5) Inorder to use Date meta tags supported out of the box, which elements in XML can be used for representing the date tags: dc.date,dc.date.valid,dc.date.valid,dc.date.modified,etc.
dc.date is probably the safest bet. Other variants can be used but if there are multiple values in different fields there is an order in which Funnelback determines the 'date' to assign to the record when it is indexed. See: https://docs.funnelback.com/customise/metadata-customisation/metadata-class-types.html#metadata-class-types-date and specifically the bit on date precedence order
6) Is the event supported for xml tag? will the following xml element work as events < dateOn>20200301|20200302|20200303< / dateOn>.
Yes as long as you are using events mode when you run the query. You could also specify that in multiple elements
<dateOn>20200301|20200302|20200303</dateOn>
could also be specified with something like
<dateOn>20200301</dateOn>
<dateOn>20200302</dateOn>
<dateOn>20200303</dateOn>
Note: events mode is incompatible with a heap of other Funnelback features so you need to be aware of this if you consider using it. https://community.funnelback.com/knowledge-base/implementation/search-interface/events-search-limitations