I don't think they can enter anymore, but could still hypothetically get a WC. I doubt Laura will play though, she still has two doubles competitions left and I think she's learnt from the AO where she ended up having to pull out of the girls doubles.
Tara did enter junior Wimbledon - irrelevant from the point of view of getting in on ranking, but a clear indication that she wants a wildcard, and I'm sure she will be given one after the last 2 weeks. The sign-in deadline for qualifying is 4pm tomorrow, so main draw and qualifying wildcards have to be allocated before then.
Laura said in her post-match interviews yesterday that she hadn't decided whether to take part in the juniors yet. If her doubles match is before 4pm tomorrow, maybe that's what she's waiting on.
Laura's not on tomorrow's schedule - I would be surprised if she opted in anyway.
However one of the Wimbledon website news items says: "Watson showed flashes of brilliance but an assortment of errors cost her the match. The experience, nonetheless, should serve as excellent preparation for her Junior Wimbledon campaign on Saturday." Whether the latter is guesswork or fact we will find out soon.